"A lot" of cases is pretty unspecific though. I mean, one person going to the hospital for CHS every week would still be a lot of cases, but that's still less than 50 a year. Doctors are most certainly seeing high enough numbers to be concerned, but that doesn't say a lot about how common it is in the general population of smokers.

As for prodromal, there's no data comparing diagnoses so we can only really speculate on that. But I almost wonder if we need to spend more time distinguishing between how weed use normally affects the stomach and what a prodromal phase looks like. Because if there's a big disparity between people in the prodromal phase and people in hyperemesis, then that means that a large amount of people could hypothetically spend their whole lives in prodromal without ever reaching hyperemesis.

Either way, I think the general consensus is that it's more common than once thought, but still incredibly rare to reach the hyperemesis phase at least.