Frame made out of bamboo, pictured here is a My Boo that touts a partnership with a fair trade social program in Ghana to make the frames.
It's supposed to be more ecological, for obvious reasons. Weight on one is about 15kg, which is pretty good for a kitted out city bike.
I can't speak to longevity of this and whether it actually pans out vs. say, a steel bike that you keep welding back together, on account of these haven't really been around too long. It's held together via a composite glue made out of hemp and resin, so at least they're following through here I suppose.
Reviews I've read is that the ride quality is really nice, being stiff yet compliant in the ride cases as to not make it a boneshaker.
Price of these is, obviously, fairly high, these'd run you around 3000€ euros, I'd argue a comparable bike made out of traditional materials would run you maybe 800€ new. But I'd argue it's more a proof of concept.
You can theoretically ship of theseus a steel bike into pretty much forever, the question is whether that actually happens. I know when I wanted to get one of my frames welded back together every bike shop refused on insurance based reasons, which is where I assume most people stop trying and just scrap it whichever way, because at that point you either gotta know how to weld or know a guy or business who's happy to do under the table deals for this type of thing and also trusts you won't rat them out
I live in a third world country we basically fix everything like this Actually near my work is a guy who fixes bikes exactly how you described We can't afford new things so we fix whatever we have
There is another guy that literally solders gpus and one that still fixes iPhone 5 and older models
I got mine fixed by a welding shop that was happy to do under the table deals, too, but looking at this country sociologically that's not the kind of skillset I'd argue most people posess tbh.
It's a side effect of living in a "richer" country Things are cheaper to replace than fix a lot of the time