I'm basing it on my knowledge of all comparable two way satellite antennas, Rx/tx rf chains and modems. But there really is nothing comparable. The cost may end up being opaque and hidden to the end user wrapped up in 24, 36, 60 month service contracts. Sort of like how you can get a $950 phone for "$0" with contract.

Current phased array two way satellite stuff that is small, and intended for geostationary purposes, is manufactured in such small quantities that it is hard to compare.

If it is cost-effective for SpaceX with 0 customers so far, do you think DirecTV, dish, etc, with millions of subscribers for more than a decade wouldn't do it? I would be good money they've spent their fair share of r&d on this, and the good ol ~70cm parabolic dish wins out. And they don't even have to solve the problem of the satellites moving.

DirecTV and others' Rx only geostationary market is 50x larger than small two way vsat, because most of the USA doesn't need vsat service. They're all based on standard cheap geostationary rx only tech. A DirecTV dish and feed + lnb are super simple and cheap to manufacture.