There may never be a wave in America again.
1) The country is almost completely severed in half politically. Nearly 50% of the nation would vote Democrat no matter who the candidate is, and nearly the other half vote Republican no matter who the candidate is. Precisely why we have these two candidates that we have.
2) Less than 10% of the voting population will actually decide the Presidency. Independents and swing voters. They make up a tiny portion of voters, and are the only ones that will vote for who they believe is the best person regardless of what party.
If it is Biden and Trump again, whoever wins, it will be by a thin margin.