You said, "he has a lot of lobbyists funding him so long as he stays in power and does what they want him to do."
Isn't that true of all politicians who take money from lobbyists and PACs? Democrats actually get more donations from corporations and PACs than the Republicans do.
So far this year Chuck Schumer personally has raised $5.5 million just from Banking, Real Estate, and Law firms alone. He is not even running for re-election this year.
https://www.opensecrets.org/members-of-congress/charles-e-schumer/industries?cid=N00001093&cycle=2020
Besides, this really has nothing to do with getting rid of the filibuster.
The filibuster was meant to force the majority party to have to negotiate with the minority party to get legislation passed. It is meant to stop one party from being too authoritarian and force a wider exchange of ideas.
The Democrats want to get rid of it because they can't sell their policies on the merits of their policies and they refuse to negotiate. We are seeing this now with the stimulus package.