I own and regularly ride some very low end stuff that had already been discarded by someone else. I don't have any problems with stuff falling apart within months, they are decades old already. The difference between me and a lot of people who buy or own low end bikes is I don't expect to get one and just be able to ride it without spending a bit of time sorting it out. first. Many buyers of the cheapo stuff are clueless, just witness how many are riding around with their forks facing back to front and the brake cables twisted tightly round the head tube. The assembly QC on cheap bikes is frankly non-existent, and if you want a cheap one to be reliable and not cost much to run, you need to build it how it should have been built at the factory, but wasn't. I spend virtually nothing on bike maintenance whatsoever, apart from a bit of lube and the odd tyre replacement, and when I say virtually nothing I mean exactly that. I'm not buying £100 bikes then spending another hundred a year fixing them. More like I'll get a bike FOC or for a quid off the 'Bay, and I might then spend a whole tenner on it over the course of the next year!