Nobody is disputing the fact that Photoshop is a more powerful single-image editor. But many Lightroom's functions other than editing can't be readily superseded by Bridge+ACR+PS.
You said "There's nothing in LR that can't be done in bridge, raw, CS" - which is a lot different than "different tools for different jobs." If you choose not to use its more advanced library/catalog management tools because they don't suit your workflow, that's no reason to say that those tools don't exist.
On a less serious note, I think something's a little off with your workflow math. If you fill up a SD card every week, and spend "a few hours" editing each image ... well, let's say you use a 16GB card, and your raw images are 30MB each, that's around 500 shots per card. Three hours per image, means 1500 hours editing this week's images. Not counting the day off to spend in the darkroom. Can I borrow your wristwatch? I need time like that.