It'd be nice if it were only one, but ask some fans of other teams how long they've had to endure dry stretches between NFCCG-caliber coaches. Some have waited decades. They don't exactly grow on trees...
And the fact that we don't have a good talent base under us defensively is something else that makes this a potentially VERY badly-timed decision. The next coach is not inheriting a good situation.
Carroll is not a NFCCG caliber coach anymore. Can you honestly say that things have been trending up with Carroll? Things have been going backwards for awhile. We have not had a top 10 defense under Carroll since 2016, which still had the remnants of the LOB. We've tried rebuilding, retooling, and cycling through three coordinators all for worse results each season.
I love what Carroll did for the team, but it was time the franchise and Carroll to move on. Things had gotten stale under Pete.
The thing is, Pete was no spring chicken either. He had one year left on his contract with an optional 5th year attached. How much longer was he really going to be coaching at a high level in the NFL? Carroll already was struggling to keep up with new NFL trends and he didn't surround himself with good people to implement the new trends in defense and offensive play in the NFL.
The writing was on the wall. Carroll was going to be gone within a season or two anyways.