SMS enabling offnet numbers has gotten stricter over the last few months, Bandwidth.com will not enable wireless numbers for SMS, and if there is an existing routing record (eSPID/NNID) most vendors require this be removed by the losing SMS provider prior to enabling a number for offnet SMS.
I used to be able to SMS enable my T-Mobile numbers offnet, but every 30 days TMobile would take this back.
10DLC is being strongly pushed by some carriers, while others are still permitting conversational traffic (for every one message that goes in, one should come back, with a 10% margin in either direction) to go over P2P rails.
With The Carrier Registry invalidating all registered organizations and campaigns every few months, triggering everyone to fill out a ton of paperwork, pay $50 or more to re-validate every business, and also the recent sudden devalidation of every sole proprietor 10DLC registration, I don't blame those who don't want to participate in this unsanctioned cartel formed by the big three wireless carriers.