If the enhanced ACA subsidies are not renewed, things go back to the way they were in 2020. Biden's enhanced subsidies were originally only supposed to be for 2021 and 2022, basically as a response to covid, then he got them extended through 2025. But this is the problem that comes back to bite both parties... something which passes (esp. with some amount of bipartisan support) because it's put forth as temporary then turns into something their advocates say must be made permanent. On our side, now it's these health care subsidies. For the other side, we see "temporary" tax cuts that they always want to extend.
What surprises me is why people ever *expect* that temporary things will be permanent, at least without a fight. There's a reason they were passed as temporary in the first place, it's always going to be a struggle to perpetuate them. Sometimes you get it, sometimes you don't. I'm not saying it's not worth fighting for, but I think it's worth remembering the context, that originally these enhanced subsidies were only supposed to be for 2 years to begin with. It's no surprise that Republicans are largely against them, they never liked the ACA to begin with. (Luckily there are a handful that still actually seem somewhat responsive to their constituents!)
Personally, as a long term solution, I see increased subsidies still a halfway measure, doubling down on a system we'd be better off transitioning out of. I think the real goal should still be some variation of the "public option" or "medicare for all" plans that have been floated. Enhanced subsidies are worthwhile for a few years at the moment, and I hope we get them, but if we get a Dem president and a Dem congress in 2028, I hope we can work toward something better than a system that is still burdened with an obligation to for-profit middlemen between you and your health care.