That ultimately hurts customers more than the data breach. Limiting access means less availability for customers. If all the customers leave, you’ve just contributed to a monopoly/oligopoly.
Or reserve it for the next company that could pony up at a significant discount.
Look - too big to fail means we let too many companies merge. This isn't a healthy situation that losing T-Mobile means having no competition left. We should probably unwind some mergers first.