I think some of the current larger flying schools (and Aero Clubs) are having a lend of their students by only having 4 seater aircraft available for training and in doing so are discouraging new starters due to cost.
Back when I learned to fly and when I was instructing we had a fleet of 2 seaters (PA38s and 152s) and a fleet of 4 seaters (PA28s and C172s). With this fleet we did or the basic training and NAVs up to 3 hours in length and only used the 4 seaters for longer the NAVs including the CTA NAV (due to lack of equip in the 2 seaters). This saved the student lots of money that they could use in the future ie CSU/ retractable.
I think most of the schools (especially the Aero Clubs) have forgotten that not everyone wants to fly for a living and there are lots of people who want to FLT for fun and obey wanted to jump in a 2 seater on a nice sunny day and go for a fly. This thinking has pushed those flying for fun to RAAus where they can fly a cheap 2 seater with lots of the RAAUs schools now like the Aero Clubs I've the past.