Philpaz, no one is disputing that the instructing/ air taxi route produces a better more rounded pilot (also note I am an ex-instructor and was very briefly a turboprop FO until laid off last year, not a 200hour jobseeker).
The other thing that has contributed to the SSTR culture is actually the switch from the CAA to the JAA training system, on the old self improver route the 700 hour requirement for a full CPL meant it was necessary to instruct to build hours, with the introduction of JAA and the fact a full CPL could be held a 200 hours has given low hour pilots the option of going straight to a type rating, and airlines have exploited this fact.