There was, but the tradition is that an incumbent president seeking reelection rarely gets challenged during the primary. Joe Biden was the only serious candidate during the Democratic primary. When he withdrew from the race after the primary, and only a few weeks before the DNC, where the nomination would be made official, there wasn’t time to organize a second primary. It takes time to generate a list of candidates, get those to each of the states, have the states print ballots and organize a special election. The DNC was forced to pick a new candidate without going through another primary because they had to finalize their choice in time for the states to organize the actual election. Many states even have laws with deadlines for nominations that the DNC had to work within.

It was going to take decades to recover from how badly Trump fucked up the government last time he was in power, and the economy was only just starting to recover. With another term, its unlikely we’ll be able to recover within my lifetime, my children will be left worse off than me.