My (cheap department store) bicycle had a sudden critical failure that caused my front wheel to lock, throwing me over the handlebars. That's the main reason I'll never buy one of those again.
Of course, that was in the early 90s, and I'm open to the possibility that cheap bikes have improved since then, but it was an abrupt lesson about getting what you pay for...
I might be overly pessimistic about the $500 bikes though; I’ve never owned one in that price range.
Everything in it is solid quality; Shimano hubs, aluminum hoops, micro shift drivetrain, threaded BB, decent headset and fork.
Unfortunately not. I thought the same but they usually come with very old parts where the manufacturer only makes that grade. Stuff like a 7s cassette: to get any better you need to drop £300-1200 and install an entirely new groupset, for example. Even upgrading your wheels starts from £300.
It’s only around the £1000-1500 point where you start getting into the realm of upgradable complements that are worth doing.