Damo I was using Bridge for two or three years before I made the move to Lr, and even though I pretty much use Lr for all of my image viewing needs, I still use Bridge quite a bit, especially when working with Adobe products other than Lr/Ps. Now that I have a system that can keep up with it I even auto write to xmp from Lr, so that I have my Lr edits always visible in Bridge.
One of the main reasons that I moved to Lr was for the advanced DAM tools. With now over 55000 images in my library I had got to the point where I could no longer easily find many of my images. My main photographic interest is aviation, and I will shoot multiple airshows at the same location. OK so I could save the images in a folder structure by location and date. But I also want to have all of my images saved by manufacturer and type. Or do I want to save them in a structure by operator? The simple answer when using Lr is to save the files in a simple dated folder structure, and do all of the other sorting in the DAM application.
I comprehensively keyword all of the images, which admittedly can take a while, but most good DAM programs have methods to help make it easier. Then in Lr I use the Smart Collection features to create a pseudo file system that allows me to group a single physical copy of an image into multiple locations, based on a multitude of information about the image, pulled from the EXIF and other metadata. The fact that the program is using a database to hold this information makes it just as quick to navigate this filesystem like hierarchy as a user as it does to navigate folders in Bridge. Of course I can also do the same directly in the folder structure too should I chose to. Lr has normal collections too, to which you manually add images, Until I moved to using Lr CC, with it's integration with Lr mobile, which allows me to easily share Lr smart previews with my mobile devices, and even the web page app, I didn't really make any use of normal collections.
I know Bridge has collections too, but it was I think only recently that it introduced Smart Collections. SC's in Bridge might be useful when dealing with a few hundred images in a couple of different folders, but it seems to fall down when you want to apply it across your entire image collection. I tried running an SC to look for one manufacturers name across my then 50K library. I know that if I had several SC's that the time it takes to collate the metadata would be the same as for just the one, but when it takes the system over 24 hours to parse all of the images in my photo library, it's scalability is still not that useful. The problem with the Bridge approach is that it literally has to traverse the file system and open either the image file itself, or the associated xmp file, depending on the file type, and then find a read the relevant data from the file. After that it has to close the file and move to the next one and repeat. It has to do this for every file, every time it needs to update. I can't perceive the length of time the DB search takes each time I click into a new SC in Lr, I certainly do notice it trawling the file system for over 24 hrs.
The other thing that was starting to become an issue for me with my Bridge only approach was managing the numbers of different versions of the same image, when saved as multiple files. I would have a CRW at the time I changed, and now CR2's too, a master PSD usually, and then maybe a couple of JPEG files, depending on what needs I had for output, web sized files, as well as files prepared for printing. Printing at home is very cost inefficient here in the UK, and I use a very good lab now that can provide me with an A3 print for about half the cost that I can print an A4 for at home. Thats based just on the cost of the paper and ink, you still have to buy the printer too. So as part of my processing flow I will often prepare the image for printing as part of the normal workflow, and then do a batch export when I'm going to send a print job to the lab.
This can leave you with lots of different versions of the image, all taking up storage space. The Lr Virtual Copy system is great for this, several different versions of the one image, from a single copy of the file. AS well as the print thing, I also have a liking for monochrome, having started with black and white film back around 1974/75 or so. For things that can be done using ACR the VC approach is great, and as far as I can see would be really simple for Adobe to add VC's to Bridge. All it would take, as far as I can see, is for Adobe to allow multiple xmp files for each image file. You would simply append the copy name to the end of the image file name to get the filename for each of the xmp copies. This would be a brilliant addition to Bridge, since it would also allow me to see each of the VC's that I have generated while using Lr, since at the moment in Bridge all I can see is the master copy of any image.
I know that for a lot of working professional photographers, shooting weddings and other general commercial work the level of DAM that is necessary is much much lower than mine. As long as the customer can tell you the date they got married for weddings finding the correct folder of images is easy. It is much the same for many other commercial situations, where you are generally producing one off batches of images, that you may well never have to access again after delivery to the client, even though you may well archive them all anyway. For that sort of use I think Bridge is probably all that you will ever really need.
There is one other thing that I notice about Bridge, no export tools. There is no way to go directly from a CR2 or a TIFF/PSD file to a resized JPEG file with applied output sharpening. You could send a batch of RAW files to ACR, or go via the Image Processor in Ps for RGB images, but it relies on having a current paid up subscription. This is actually one of the great things about Lr, even if you are running it in free mode without a subscription, you still have full access to everything other than the develop and map modules. So you can still export your images, either via the export dialogue, or in the Print, Book, Web, or Slideshow modules. I think the only export option you lose when using Lr in the free mode is the Edit in option from the right click menu. So potentially much better functionality than for Bridge without a subscription for access to Ps. Actually Lr still lets you import new images to the library, and apply the full range of metadata changes, except drag and drop geolocation. It is even possible to do basic edits via the quick edit tools in the Library module, you can also use quick edit commands on video, which you can't open in the Develop module, so you can adjust video WB and exposure etc. It does limit you to applying only one preset, as it first resets the image before applying a new preset. All of this without a subscription.
Remember that Bridge is now free, no need for a paid sub for any of the Adobe CC suite products.