"Needing" to reduce reliance on cars is debatable; that's certainly one way but not the only way. I doubt Musk would deny that replacing all cars with EVs would be enough. That's why Tesla also offers the solar roof (which needs more attention from Musk IMO) and grid level energy storage.
Tesla has discontinued the solar roof, as far as I know. That was basically just a stunt to use Tesla's money to bail out Musk and his brother. The solar wall is a better example of what you mean though.
People are great at finding ulterior motives for people they've already decided they dislike. I don't think Musk is an altruist, and I'm certain he has multiple motives for the ventures he cares about, but I think it's hard to deny that he's found success where others have struggled, and that his ventures will ultimately benefit humanity.
You can order it, but apparently [0] they are deploying on the order of ~20 per week overall, so it's unclear if you'll ever get one. You're right though that it's not discontinued - sorry about that.
