Not many advancement opportunities for individual contributors. Over time, as team leads grew into Directors, members of technical staff only got to senior level, and senior got to principal.
Relatively flat reporting structure worked great up to a certain size, but at some point the company outgrew it.
Until recently, comps were not keeping up with the market, and new-hires (some through acquisitions) were coming in with inflated titles and packages. This also significantly diluted the culture.