Thats what the elite QB's get paid for.
hes a cut below elite, but still a good starting QB.
I dont love him as a player, but I also dont see a better alternative for San Fran. I think the deal is fair, and if they get/keep the right pieces in place around him I think he will be productive enough and the team has an outside shot at a superbowl.
last couple years the biggest hindrance has been the relative health of the players around him. but then again, this has been a running theme in San Fran as they seem to have more injuries on average than most NFL teams in recent years.
but that isnt Brocks fault and I wont go into that issue here.
hes a bit of a system QB but thats not an issue so long as the coach remains and he stays on the team. I think hes his best version of himself in San Fran. I dont think he goes to another team and performs better. so this move was good for both sides and the money is at least in an acceptable range for both sides.