The enhanced subsidies are available at incomes over 400% FPL.

"Enhanced subsidies expanded income eligibility for the Affordable Care Act (ACA) to over 400% of the federal poverty level (FPL), eliminating the "subsidy cliff" for 2021-2025. Under these enhanced subsidies, individuals with incomes above 400% of the FPL (roughly \(\$78,800\) for a single person or \(\$163,200\) for a family of four) can receive subsidies if their premium for a benchmark plan exceeds 8.5% of their income. The enhanced subsidies, however, are set to expire at the end of 2025 unless Congress acts to extend them, at which point the previous 400% FPL income cap will likely return. "

There's still a limit of sorts, but that's clearer. And we know only ~22 million people are on it. AI synopsized it better than I can. :) I wonder how they decided on 8.5%? It's a sliding scale built so that lower incomes pay less and the more you earn, the more you pay. I was talking to a fellow from Denmark and he laments his health care now costs 2000 Euros a year, with a 400 Euro cap on prescriptions. I remember years ago there was an old couple on the board and they were paying close to $40k for health insurance. I think I've been lucky, but not as lucky as that Dane. :)