I think what you are talking about here is urban sprawl when you talk about things being sparse. Urban and suburban shopping mall are gross, I agree. Car centric infrastructure gets so tiring, even though we all find it convenient. Urban sprawl often brings urban blight but I can't say I've seen too much blight in my time in vegas...except in places near downtown which has a ton of prewar and per-automotbile infrastructure and I am not sure what I am missing on why the area hasn't been rejuvenated. I do have a couple guesses though.

As for loneliness I don't think that's a vegas specific issue. https://en.wikipedia.org/wiki/Hedgehog%27s_dilemma

The two points you make in your last paragraph, every city I've ever lived in has singles with the same complaint, at the same time you can be more marketable in different locations. But they say 'No matter where you go, there you are.'