As long as you don't live in rural areas and maybe the suburbs. As long as you leave your door open ...
T-Mobile CTO says 5G’s high-frequency spectrum won’t cover rural America.
arstechnica.com
One would hope. If they can figure out a way to return to caps or charge extra they will. Verizon said they never would remove them until T-Mobile forced their hand. AT&T kept increasing the cost and refused to add extra services (such as tethering) to their grandfathered unlimited plans to force people to drop them.