I watched the announcement. Knowing Musk, I'll believe it when I see it, but it sounds promising. Apparently the G2 Starlink satellites will be equipped with large antennas to support cellular users on the existing spectrum. Video was live-streamed, and still available here: https://www.youtube.com/watch?v=Qzli-Ww26Qs
Self-driving cars have proven harder than expected, but given the rest of Musk's tale, I wouldn't bet against him. SpaceX is already launching satellites, and Starlink is already providing service. T-mobile owns the frequencies for it, it's "just" a matter of building the satellites and putting them into space. If the claim were more outlandish, it would be harder to buy, but the technology is eminently doable.
Expected by whom? People who didn't understand the problem presumably.