Specifically MVNOs would be stupid to do this since they are leasing from primary network operators (Verizon, AT&T, T-Mobile) and have to play be the rules of the contract with those companies.
Plus in OPs case Visible is owned by Verizon and Xfinity runs on Verizons network. It’s not Xfinity’s interest to piss off Verizon who could kick them off their network. That would result in less negotiating power with other networks and result in higher costs for them.
Unfortunately they are already in the market and making a mess: https://www.theregister.com/2024/07/21/crowdstrike_linux_crashes_restoration_tools/