It's meaningless to compare the market caps of those 24 public companies from 1999 (that had IPOs within that year) to the valuations of those 5 private compani

It's meaningless to compare the market caps of those 24 public companies from 1999 (that had IPOs within that year) to the valuations of those 5 private companies from 2011. Companies are doing their IPOs much larger and later than back then.