Agreed, but this was the whole point in announcing a shutdown years in advance so other options could be put in place like upgrading hardware to support 4G/5G or fixed line internet. If this was sprung on people with a months notice I would think it was ridiculous, but we've known about a shutdown for years and the writing has been on the wall for probably close to a decade.
What people don't realize is there's actually a huge difference between 2G/3G and 4G/5G and it is time to get rid of the former. I expect 4G to stay around for some time as it doesn't have the same cost/extra system complexity that maintaining a 2G/3G infrastructure does.
The question isn't notice, the question is who pays for it. Say the elevators in the empire state building currently rely on 2G for backup comms. The elevator company installed that module and arranged for a service plan with Verizon and Verizon understood it was for critical safety infrastructure and they charged a high rate accordingly, and now the Empire State Realty Trust now pays those bills to Verizon.
Verizon doesn't want to pay to upgrade those elevators, but neither does the elevator company nor Empire State Realty Trust. Empire State Realty Trust might pay for the upgrade if its included next time they have someone refurbish/replace the elevators, but that might not happen for decades. The elevator company has nothing to do with really, they delivered what was purchased and owe nothing. Plus, the elevator company and Empire State Realty Trust don't care about 2G/3G/4G/5G. It's a safety backup comm, the underlying tech makes no difference. As long as it works, that's all that matters. And they've been paying Verizon for a long time to make sure it works and keeps working. Really, it should be on Verizon to upgrade or subsedize the cost of making these upgrades because they have the most to gain from moving everyone over to 4G/5G.