Absolutely. For more progressive democrat voters already been harbouring bad feelings around the legitimacy of the establishment candidate from previous elections. The two party system already loses a ton of the feeling of choice and participation in Americans. The primary is the escape valve. It is supposed to be when people that care about politics get to argue about policy, direction, etc. Even if you don't agree with the final candidate, you feel like you helped shape the direction of the process. By skipping this, even if there were other circumstances, it feels like a huge turn off for that base of the party.

And then for other democrats, the feeling when you have an unpopular president like Biden was seen at the time is to go anti estabilishment. But Kamala was Bidens VP. She couldnt run an anti estabilishment campaign when she was part of the estabilishment.

If there had been a primary, whoever was the candidate, even if it was Kamala herself, would have been much better positioned for the General Election.