Last point first, I think the issue is the very cheap FS machines are essentially BSO's, and if you combine commonly maladjusted BB and wheel bearings with a moveable rear triangle, you end up with no end of problems with gears changing when you don't want them to, and not changing when you do want them to. Then you've got the incessant squeakng and rattling that emanates from the springs in the forks and rear suspension unit. I just view bikes like the Indi pictured above, as mechanical parts donors, and the frame & forks as scrap metal. The wheels, cranks, BB, shifters, gear mechs, brakes, and bars tend to be pretty much the same quality as that used on low-end rigids and make useful spares.
In the real world, the average price and quality of bikes is nothing like what the content of cycling forums would have you believe. The vast majority of bikes are low end models bought by people looking for cheap utility transport and minmal exposure to financial loss in the event of theft. The bike racks outside shops and stations are full of low end models because they do exactly the same job as the expensive stuff without costing a couple of months wages.
Their owners couldn't care less they weigh a few pounds more or the shifting qualiity of the basic drivetrain is a bit agricultural. It gets them to the station, to the shops, or to the pub and that's the whole reason they own a bike in the first place.