>Honestly, I don’t know the full details, but I still hold that Forstall took the fall for the poor execution of Williamson in the Maps debacle.

Well that's not true because Eddy Cue fired Williamson [1]. Maps might have been the straw that broke the camel's back, but Forstall was fired also because he couldn't work well with Bob Mansfield (who came back out of retirement after he was gone [2]) and Jony Ive.

[1] https://www.cultofmac.com/203032/apple-svp-eddy-cue-fires-ri...

[2] http://allthingsd.com/20121101/behind-silicon-valleys-un-ret...