You are correct. The Supremes will rule the subsidies illegal. Then the real fun will begin.
Retroactively? Will zerocare plan purchasers have to refund the subsidies they were given? I’ve seen SCOTUS find against a plaintiff in my home town here because finding FOR her would affect police department tickets by the millions all over the country. Attwood v Lago Vista PD, about 12 years ago, O’Connor wrote the majority opinion.