One of the major issues, is that PPL training is usually done by an RF (registered facility) whereas to be able to train for the CPL or IR, you need to be an FTO (Flight Training Organisation) this involves a lot of money and hassle for not an awful lot of reward. So whilst you can get paid more per-hour, your overheads go through the roof.
Aero's, mountain flying, grass strip etc.. is usually offered anywhere decent, but many clubs don't have access to either FI's capable of teaching these things or aircraft that are suitable. (My club can, but we are unusual in that respect in our area.)