Shimano is one company that is doing alright to its customers in my opinion. While they do sell expensive top-of-the-line equipment, their cheap stuff is incredibly well built and very durable.
I agree completely. I've had lower-end Shimano components on my vintage bikes that are still working just fine 30 years later. And even the mid-range 105 components are still very affordable.
Yes, my Tern folding bike has a Shimano Claris 1x8, and it's been smooth and trouble-free for over 5000km so far!
To be honest, "low end" and "high end" doesn't really mean "one will work and the other won't". I think people assume that entry-level means it's crap. Really, you're only paying for a lighter and faster shifting system, often with fewer jumps between cogs, when you spend more money.
Any components that are dialed in will work regardless of where they fall on the spectrum.