I appreciate that this is probably true for the majority of people (at least in the west?) but it certainly doesn't apply to me, nor some of my friends.
I like not having a front/back yard to maintain (I don't enjoy gardening). I like the views that you can only get from higher floors, especially city views. I've even come to rely on some of the conveniences, like having a mail room with someone that'll sign for packages while I'm away.
And that's not to mention the many benefits of living in a higher-density neighborhood, which would be impossible in a place full of semi-/fully-detached houses.
> No-one wants to live in a block of flats unless they're too poor to afford a house.
I almost have the opposite view to you, which is that I wouldn't give up my apartment lifestyle unless I was priced out of the city, and could only afford a house in the suburbs.
In the end it's up to personal preference, and you're certainly welcome to prefer a house. But don't assume that everyone has the same preference as you.