In the UK, the varieties in the stores are a small fraction of the varieties that exist. You'll find some more as apple trees in garden centres. But I've never seen Lord Derby cookers (excellent flavour and keepers still got several trays from last October), Ashmead Kernel, Sunset or Scilly Pearl eaters in the shops. Heck it can be hard to get hold of Russets - they used to be in the shops, now I mail order 10kg every winter because even with our own tasty apples I really like some russets each year. In fact, I'm eyeing up what I've got left and contemplating another 10kg before they're all gone. It's surprising how well they stand up to being stuffed in a box and delivered, a few get bruised but I've had them about three weeks now and most are in good nick.
An awful lot of store apples are Cox's variants, or big overly juicy, red shiny flavourless bits of fruit bowl bling.