It's actually much more because the DSLR companies, for the most part, are technologically-backwards, and don't get things like platforms, APIs, or similar. It's nineties-style closed thinking. It's a big part of why cell phones are now eating their lunch. I used to be a pretty serious photographer, and own probably $10,000 worth of camera equipment.

I mostly shoot with my cell phone these days, not because I mind spending money on cameras, but because it's a better device for most photography. It integrates with the world. Cameras integrate with their manufacturer's closed ecosystems.

USB Video class allows the device to provide a list of formats supported, and the host to choose one. That seems suitable for the host to manage bandwidth across its USB links, even if other devices are also using bandwidth.