Belichick lucked out with a QB in Brady, had a good base that was partially built up with Carroll, and had a solid draft after 2000. He also didn't inherit a 4 win team. He inherited an 8-8 team. His first year he dropped to 5-11. Mayo inherited a 4 win team with far less talent that also has huge injuries on defense and the offensive line.
We don't need to revise history. Mayo is not coming on a team that already had a well established franchise QB in Bledsoe (he currently has a rookie who only started a few games), Ty Law, Troy Brown, Damian Woody, Willie McGinest, Tedy Bruschi, Lawyer Milloy, Kevin Faulk and Adam Vinatieiri as a baseline to build off of. We aren't a rookie Tom Brady coming into his own, Matt Light and Richard Seymour away from really taking off. There's a lot.
Right now we have Maye who is a rookie and trying to become a longterm franchise QB and Gonzalez are the two players you could theoretically have as part of a longterm build. The next two best players are Keion White who is a longterm guy and Hunter Henry who is going to be 30 in a couple of weeks and can't be looked at as a guy who will be here for the next 3-4 years. Literally everybody else is expendable and could be replaced.
This is a longer rebuild whether you like it or not. Maybe we can be more competitive in two years instead of 3-5. But it's not a quick fix. There's just far too many holes. And yes Mayo has had problems, but guess what, Andy Reid isn't going to come and take this team to the playoffs. We saw what Bill Belichick did last year with the team. We need to stop pretending there are any quick fixes. We spent way too long avoiding this and trying to patchwork a team because we had Bill and it just got worse and worse. They needed a rebuild for awhile. Now's the time to rip the bandaid off while you have a QB who should be here for 15 years.