Sure, but all those brilliant songs are going to waste and no one but serious Weezer fans will ever hear some of the best stuff he ever wrote.
They could just keep releasing simple 'good' albums every year, but SFTBH is a guaranteed standout and success. We know this from the majority of songs that we've already heard which are superb. Like the OP said, it's totally win-win.
But then again, Rivers doesn't take advice from fans. So, I'm just hoping SFTBH is finished and released sometime in the future.
I'd rather hear a new great album than hear him revisit SFTBH and get an album full of mostly old songs I've heard before.
I may be alone in saying this but I know Weezer has a great album in them after seeing them live this past year. They seem totally re-energized and Rivers understands what makes a great Weezer song now more than ever.