[analog31]

From what I've observed, moderately priced bikes tend to be more sane in terms of adhering to mainstream component standards. For instance I bought a fairly generic "sporty looking hybrid" in 2006 for which I've had no problems sourcing parts -- although very few parts have been needed. Outside of competitive or off road use, good bike parts are actually quite reliable and last a long time.

Trek, Giant, Specialized, Raleigh, Fuji... Some of these have become "just a brand name" under new ownership.

I also have a bike that I threw together from 40 year old parts, and can still get any replacement that I need from Amazon or eBay. I suspect demand from overseas may be keeping some parts for older bikes available.

I think you can contribute a lot to the lifespan of a bike by learning to do a bit of your own maintenance, so you can spot minor issues before they turn into component failures.