A big part of this is that a lot of varieties don't travel well.

But commercial apples like ambrosia and honeycrisp do and are pretty tasty. Ubiquity of red delicious is sort of baffling.

There's also a huge chunk of the country where apples don't grow well due to lack of sufficient freeze.

Visiting orchards in Autumn was a fun annual tradition when I lived in the Northern US. The whole fam would enjoy those days together picking apples. No orchards nearby this part of Texas, though.

I live very close to where the Honeycrisp was developed, and sadly I don't frequent them or the other local orchards as much as I should.