As someone who uses both medium format digital and 35mm digital, I believe that the current price drop is a combination of things, not entirely attributed to the most recent offerings of canon and nikon.
First off, the H4d camera system that is now on sale, was released in 2010, the H3d was in 2008, and so on. This could be one implication of an attempt to clear stock before a supposed 'H5d' comes out. As of now that is just a speculation.
Secondly, despite what canon and nikon currently offer, even considering the D800 with its 36mp sensor, it still does not match the quality of medium format digital. The current hasselblad HC fujinon lenses are actually sharper then the old CF zeiss lenses, and the way they render an image is actually sufficiently better than any canon I have used (I have owned several canon flagship bodies, as well as lenses and still believe the hasselblad 80 f2.8 'kit' lens blows any of them out of the water. Part of it is optical design, another part is the quality of the glass and the actual lens. Quality control is much greater than canon or nikon who create and pump out lenses at massive volumes. Canon lenses in particular are 'sharp' but ultimately lack tonal quality, I will admit that the nikon G lenses, in particular the 85 f1.4 G do come close to the D800's resolving power though.
Another thing to consider is as someone previously mentioned, a lenses resolving power. If you use a not so good lens on a large MP count body, it really shows. Again having shot with and tested a D800, the G lenses performed well, typical other lenses really started to fall apart on the larger sensor, but by no means did it compare to a Phase One digital back with a Fujinon lens in front of it. If anything, Hasselblad has to worry about Phase, because they are currently the leading medium format digital entity (they have acquired both Mamiya, Leaf, and work closely with schneider)
Lastly, for professional use, medium format digital has no second (at least in regards to digital)
Most professional photographers are typically going to also be using profoto or broncolor lighting, with all the modifiers to make the light look great, even on location. Having the high sync speeds that only medium format offers with its leaf shutter lenses is a huge advantage. Lets see any canon or nikon body shoot at up to 1/1600 with a legitimate studio strobe firing and syncing with the flash. I am not talking about using a speed light and high speed sync, that won't cut it in a broncolor para 330. Also for a professional using this type of equipment, using a Phase One IQ180 delivering 80MP files which can be blown up to billboard size, as well as the back having a touch screen that is up to par with an iPhone 4s, makes it a great combination. As for battery life, most of the professionals that use these cameras shoot tethered into capture one, where the back is powered by the firewire cable.
Now, if you have read all of this you may think, sure 35mm can't do a lot of that, but it can do so much more!
Very true, 35mm cameras dominate in some fields, but not all. This includes: frame rate, ISO, focusing, and lens options.
If you are shooting an event such as a wedding, or a sporting event, you want a body that can hammer out frames for hours on end, can handle any lighting conditions the world may throw at you, and be able to capture that precise moment that counts. That is why most professional photographers that shoot medium format digital, also own a 35mm camera, despite it being Canon or Nikon. Don't forget video, these cameras can do high definition video in an affordable package that mostly anyone can afford these days.
Not everyone can afford to shoot with a high end camera like Hasselblad, Phase One, Red One, or Arri, but the high end professionals do still use them and there will be a market for them. A perfect example is the new Marvel Avengers movie was shot with Arri Alexa cameras (100k+ digital 4k cameras that are better than RED) but still used Canon 5d Mark IIs for a lot of the smaller action scenes. Why you may ask? It's small, portable, and costs 1/40 of just 1 Arri, that's much easier for them to accept the camera getting damage or trashed.
35mm becomes increasingly competitive, but the pros still use the pro systems.
Sorry for the long post, but it needed to be said.