One thing I realized in the wake of the whole "Kamala Harris proposes hilariously convoluted meager student loan reimbursement scheme" is that socialism faces a very peculiar problem in winning over centrists/liberals, and that's just that it's so much more simple that it turns them off.
Liberals seem to love thinking of these outrageously complex plans for solving problems with relatively straightforward solutions because of their predilection for that kind of "work smarter, not harder" philosophy and how much they love affixing the "smart" onto everything like a prefix. Smart power, smart diplomacy, "put the smart people back in charge" etc. So if someone comes up with a plan that has like fifty different levels of micro-targeting to it with varying clauses, it's like their eyes just glaze over and they think "wow, this is so deep, this person has a Serious Plan" and when a socialist just says "We will just straight up abolish the student loan debt" in comparison, those same people just kind of scoff and think "oh, pff, you think it's that easy? Try being Serious for once."
It reminds me of needlessly complex gimmicky weight loss regimes. A few years ago I decided I wanted to lose weight and dropped around 30 pounds, and whenever someone in my family asked how I did it, it was like my answer actually upset them - I cut out soda and just ate less/broke smaller meals into tinier portions to sate cravings. They wanted some sort of complex secret, but the answer was just so simple and straightforward it was disappointing - you consume less calories, that's it. Socialist policy to social and economic problems is often so straightforward I think it turns some people off because so many people have internalized this silly idea that the best kind of policy is the kind with five thousand layered levels to it and anything that just proposes something like "Actually, just give poor people more money" comes off like it's childish and dumb.
Bernie has a closely related problem in how he actually identifies root causes to most issues - it annoys the hell out of some Liberals that Bernie brings up "the billionaires" in response to most issues, because he correctly draws lines between issues instead of treating every single one of them like completely separated, individual problems with no shared cause. The idea of it being that straight-forward, again, is drilled into some people as not being credible, somehow.