T-Mobile has a three decade head start (maybe four if you count their Sprint Wireless acquisition's history), so hardly surprising if there is currently more T-Mobile home internet users than Starlink users. But I also doubt that their rural base is as large as Starlink's currently is. Mobile broadband speeds heavily depend on the strength of the signal available in area, and in many rural areas, the 5G coverage is extremely spotty, or non-existent.