Dems definitely lack a coherent, interesting economic message. Any new proposal - medicare for all, UBI - immediately gets sucked into a quagmire of details. Turning to Republicans for the votes they need to win in general elections has been such a consistently losing strategy that I have no idea why they keep doing it.
Meanwhile Republicans keep running on "You feel poor and it's Their fault," continues to resonate, for varying definitions of "Them," as long as GOP is out-of-power. It's simple. It feels good. It completely absolves them of needing any policy more complicated than "Get rid of Them." It's a winning strategy as much as the Dems have a losing strategy.
The filibuster is just a Senate rule, though, which they can rewrite any time they like (though usually only after an election).
The 2017 repeal effort used a budget reconciliation mechanism that is not subject to filibuster. In fact, a lot of the 2017 legislative awfulness used the budget reconciliation hack, where the Senate can change laws in order to 'balance the budget,' so long as (by convention) they don't change policy. 2017 repeal, of course, famously failed because John McCain thought they shouldn't use that process and voted against it.