It would have been water under the bridge if him and his cronies all got perpetuity starting jan 7th and we never heard of them ever again. Instead the dems chose a demonstration of weakness, and showed that an attempt on our democracy would be punished by a strong worded reprimand, at best.
It wasn't up to dems but courts imho.
Plenty of blame to go around including for the Democrats.
Responsibility for Merrick Garland's failure to adequately pursue Trump lies at Joe Biden's feet and will likely be the thing he is remembered for most in the history books* despite the fact that he had some decent domestic policy (and some horrific foreign policy).
* (assuming we work our way out of the current mess, if we don't he will be remembered for far worse things given that he's Trump's reflexive whipping boy despite the fact that it makes Trump look weak to keep droning on about Biden)