It's a really bad idea, because if the Democrats can increase the court enough to swing the balance back to the liberals, what should they expect the Republicans to do when they regain power?

Right now, supposedly the court is 6-3 in favor of the conservatives. So if the Democrats increase the court by 4, to swing the balance to 6 conservatives and 7 liberals, then when the Republicans regain power, they will increase the court by 2 more to swing the balance back to 8 conservatives and 7 liberals. And within a generation, the Supreme Court will be as large as the Congress, and just as political.

I don't think there's any appetite for this. Biden says he's going to establish a commission to study it, which is a common political trick. Commissions are where ideas to go die.

---