The only reason they would try this again is if they were sure he was going to win. If Trump is far ahead in the polls and they steal the election via mail-in fraud, it would look suspicious. But if Biden is "ahead" in the polls, nobody will bat an eye if he wins.

They know he's going to win and will make sure of it.

When Hillary was yelling "why aren't I 50 pts ahead you might ask?", She wasn't yelling at you, she was yelling at the riggers for failing.