I think such a progression is natural.
I started with
Romans, most of them late
Romans, but after a while they became boring,
too close to collecting modern coins for my taste. So I went to
Provincial coins from the Balkans.
After a while it was the same here. The
rare reverses are expensive and you can only see so many
Homonoias before you're bored out of your skull. Minor differences in busts, legends or combinations thereof
are not interesting to me although they make almost all coins
rare.
Asia minor is not only more interesting but more varied as well. As a focus it REALLY broad
but I
still often deviate. Silver didn't interest me at all but Greek Silver is something different.
I'll probably never really collect them but surely buy the occasional
tetradrachm.
Greek bronzes are beautiful as well and often very affordable.