Actually, Montana took KC to the 1994 AFC championship with a bunch of receivers you've never heard of and followed that up with another playoff appearance in 1995 before calling it a career. His production only dropped in my mind because of mounting injuries. He had major back surgery in the late 80's and a nasty elbow surgery and rehabilitation in 1993.
No question he wasn't as durable as Favre. Favre had some great offenses in his prime years so you can't put it on Montana having Jerry Rice. Every great hall of fame worthy QB in NFL history had a great go to receiver.
The offenses Farve had were not that great talent-wise. He had good tight ends for one year 95-96. He had Sterling Sharpe at wide out for a couple of years before the packers got good. He had Antonio Freeman--a slow footed receiver. And he had Robert Brooks--good for a year or two then he blew out his knee
The packers won the superbowl with journeymen wideouts and a second rate running game.
Montana had the finest mind of any quarterback. He had an average arm and feeble physical skills, but like Larry Bird, he thrived b/c he was brilliant. In my opinion, Montana is far and away the best quarterback of modern times. The only guy coming close to him is Tom Brady.
Everyone else is a footnote.
...and I'm a green bay fan.