@tsarstepan,
You brought up Biden. Now you are whining because I responded to your off topic post? Geez!
We have a two-party system. The system works (and evolves) because both parties are after voters. The Republican party will do what it has to do to survive, and the Democratic party will respond. You can't talk about changes to one party without understanding how the other party is responding.
One possibility is that the Republican party swings to the center. I see the Democratic party becoming more extreme, partially because after Trump there is some slack for them to move to the far left. They counted on an anti-Trump vote that they may not be able to depend upon in future elections.
Trump upset the system. I suggesting that what we might see is overreaction, adjustment and then resettling on both sides.