Devil's advocate:

Biden's weaker right now than ever before and he's the millstone sinking the Demonic Rat ship, enhancing Trump's chances.

Impeaching him only does one of two things:

1.) The most likely event that the senate will acquit him, and gains a very talking point that he beat back an impeachment, just like Trump. That'll power-up Biden's side while neutralizing one of the most powerful points Trump has. The result is a strengthened Biden and a Weakened Trump: Unacceptable.

2.) In the unlikely event that Biden did get removed from the office, it is likely that the Demonic Rats will use him as a scapegoat for all of the the troubles we are experiencing (well deserved, but a good portion of the blame should be shouldered by these jackasses) and then float in a fresh face against Trump. Might not do well, but having the fresh face is a potential advantage that we cannot tolerate from the Demonic Rats.

In short, why impeach Biden so late in the game? 12 months will fly by before you know it, let's use that time to kick the Demonic Rat's ass and get Trump back into power.