Why would people go to towers from the south? For thrills, they have Thorpe. For family, they have Chessington, LLW and Paulton’s.
I think towers have lost their way and therefore a decent slice of the market.
For me, Pleasure Woodhills or Great Yarmouth Pleasure Beach are my closest park, but not worth the visit.
Thorpe, Chessie and LLW are the closer Merlin Parks in distance compared to Alton, but the M25 traffic means that Alton is actually the quickest option for driving for me, plus I prefer the rides at Alton.