I don't really many (or any?) people suggesting that they're currently using 5G modems. Just that it is a likely next step assuming hardware costs go down to make it worth the hassle as a secondary channel.

The public wifi one is funny. It seems totally like something they'd do, but totally open wifi doesn't really exist anymore so the window for that scam is likely closed. I doubt they'll bother with it at this point.

More likely would be cutting Comcast in on things in return for using the public wifi channels they have on their customer's routers that they already use for cell service. But it might be easier/cheaper to just make not connecting to wifi more and more painful for customers instead though, you only need to trick/wear down one user of the household to win this battle so if they just slowly turn up the harassment feature they'll get 99% of people in the end.