Getting rid of the filibuster only requires a majority vote. We don't have to do a damn thing to get Democrats to get rid of the filibuster, they could literally do it today or at any time in the last 3½ years. But they won't. Because they like the status quo. It gives them a reason for why they don't get anything accomplished and allows them to raise funds by making false promises.
They had all three for 2 years and did nothing. For the same reason.