You argue that we shouldn't care what the market did between 1929 and 1960? Then why should we care what happened in 1999?
Closer up, returns have been good. One year return is excellent, five year return is extraordinary, ten year return fine.
SP 500 1 year: +21%/yr
5 year: +19%/yr
10 year +6.7%/yr
One interesting thing - from the inception of the vanguard sp 500 fund in 1976 the fund is up an amazing 10.9% per year.
You call that a transition to a rangebound market? Really? 19% per year for five years?