First the super majority isn't a constitutional or even legislative barrier. It's simply a Senate rule. Rules for the Senate are established at the start of every Congress. There's no reason why the Senate couldn't simply eliminate the rule.
Republicans like the filibuster because they can force through most of what they want under reconciliation, which only requires a simply majority, and they can block Democrats with a minority. Democrats like the filibuster because it gives them an excuse to do nothing. Because a lot of what Democrats want to do isn't filibuster-proof.
Also, the filibuster once meant that you had to stand up and hold the floor to block a vote. Now we have a silent hold since the 1970s. If you for some reason believe in needing 60 votes to end debate, why not at least adopt the earlier interpretation that requires someone to stand at a podium? Because Democrats don't want to do anything. That's why.
Biden had four terrible decisions in his presidency:
1. Appointing Merrick Garland as AG. He's another establishment Democrat that didn't want to do anything, really, particularly not prosecute the insurrection that took place. He was embarrassed into doing so by the January 6 Committee. He basically lost 2 years of potentially prosecuting the administration;
2. His Israel policy, particularly the bear hug strategy and especially not ending the genocide;
3. Not raking MBS over the coals for not ending the Trump 2020 OPEC deal, wich exacerbated the inflation price shock; and
4. Running for re-election.
It's worth adding that the only reason Biden was the candidate was because the DNC was scared Bernie Sanders would be the candidate so they fixed the race in South Carolina thanks to Jim Clyburn in particular. Everyone dropped out of the primary and got rewarded with Cabinet posts, etc (eg Pete Buttigief as DoT Secretary). Except one. Elizabeth Warren stayed in to split Bernie's vote.
As for blaming the voters, I 100% disagree. The party leadership has repeatedly engineered situations to give the voters terrible choices and rely on lesser evil voting. After the 2017 election, the DNC got sued and argued in court that they had no obligation to stay neutral. That was a political promise not a binding promise. Basically, they argued that they were free to overrule the will of primary voters with superdelegates and manipualting of funds by then DNC Chair Debbie Wasserman Schultz, who when exposed and was forced out, just went and joined the Hilary campaign.
Voters stayed home in the millions in 2024 (vs 2020) because they were given no choice. They're not responsible for that. The candidate is. And if you end up being angry about Kamala losing, blame her for having a terrible platform, not the voters who decided a slightly better candidate was the only available choice.