Telephone networks are a dead business. You look at European telecom stocks and they just keep going down year after year. Wont be long before they're all bankrupts and will get nationalized again.
Just as a quick example, the supermarket down the street from me is neither expanding their market or entering a new line of business. There is no risk of a Walmart opening next door given the location. They just seem to be doing just fine selling the groceries people need each week.
Yes, sometimes market conditions change, and the companies need to react. Maybe people prefer buying avocados instead of carrots this season, and they need to adjust their stock. But outside that, there's no need for them to radically expand to stay sustainable.
IMO, this would be a bad move. Let them die. Voice and text over the internet is here to stay. In the last two years I didn't a single phone call thanks to WhatsApp, Signal and Instagram.