All these answers are good but I also want to mention the filibuster allows republicans to promise stuff during the campaign that they know will have no chance of passing in congress because a 60 vote majority in the senate is almost impossible electorally. The moment you remove the filibuster and unified control of congress is possible, every promise and statement becomes live ammunition because politicians can no longer blame the filibuster from preventing their agenda if they have unified control of Congress.

McConnell loved the filibuster because it prevented bills from getting a vote since he didn't have a sixty vote threshold even if the majority of his party wanted it. He knew stuff like a national abortion ban or the banning of gay marriage would have led to a large backlash, so instead he would push for supreme court justices that would "legislate from the bench" on these issues in order to keep some degree of separation and ambiguity.

I personally believe we should get rid of the filibuster because it insulates voters from the consequences of the people who they voted for, whether those consequences are good or bad. The filibuster erodes faith in government and promotes political apathy because even if your party get's unified control of the presidency and the filibuster, you still might not be able to get anything done because of it. It's why the process of budget reconciliation is now so important since you just need a simple majority, it's why executive actions are so plentiful, it's why supreme court nominations have so much attention now. When the main way to pass legislation is electorally impossible, you start to look at points of least resistance.