This is the direct result of the merger of Sprint and T-mobile. They swore up and down to congress they would NOT raise prices on consumers[0]. So instead they turned around and like gangsters would do said to every business in the US sending text messages: "It'd be a real shame if those texts reminders you wanted to send stopped working... Good thing you can instead pay us $40 / month to be sure those messages are delivered."
At the same time At&T and Verizon saying oh snap let's make money on this too and still being pissed about Stir Shaken so to get ahead of it for Texting before Congress forces it on them. This way they can make money on it before it's forced.
[0] https://fortune.com/2019/02/04/t-mobiles-john-legere-promise...