After a lot of negotiation, The Big Bang Theory has been renewed for seasons 11 and 12. For a while I wondered if the people behind it wouldn't just say "we've done enough, time to move on."
But it's still the biggest hit CBS (or any network) has (especially taking the demos into account), so what were they to do? Some people like to go out on top, but others like to keep on going until it's definitely over. It's hard to imagine making that much money, but it's also hard to imagine giving it up when you don't have to.
There's also going to be a spinoff called Young Sheldon, which sounds awful. Sheldon, unquestionably the breakout character, works fine playing off the ensemble, but I don't want to see him surrounded by new characters, I don't want to see his "origin" and I don't want him played by a new actor.
Still, who knows? I recall, a decade ago, seeing a huge billboard near where I live advertising this new show called The Big Bang Theory. It featured the three leads, Kaley Cuoco, Johnny Galecki and Jim Parsons. And I remember thinking "isn't it sad?--here are these young actors all excited about landing a network sitcom, and by the end of the year they'll probably be canceled and forgotten."