But a bike for $60-90 is not a new idea. They're out there right now.
I very much disagree with your stance on this. I have yet to see a cheap bike that will stand up to more than a few months of daily commuting without various bearings wearing out. Use of non-standard parts makes fixing them uneconomical, as you could quickly buy a decent bike for the replacement value required.
I'd argue that the cheap bike problem is only currently solved in that cheap, good quality, second-hand bikes are available in most markets.
If this bike barely lasts as long, it'll at least have sold the problem of having all these useless lumps of metal lying around once your cheap bike has died.