If it helps to have the perspective of another BMW owner: My husband currently drives a 750i and, until I got my MS 70D almost 2 months ago, used to talk about how much he loved his car, couldn't wait to drive it, etc. Ever since we got the Model S, all he wants to do is drive my car, and mine is only the 'baby' Tesla. It took him all of about 3 weeks before he was completely converted and ordered his 90D. He said he would get in his BMW and wonder why the accelerator didn't immediately respond, and find himself doing burnouts accidentally. Too funny! He works in tech and so is very well connected with the idea of obsolescence, and so considered waiting for more advancements for like a hot second, but ultimately the joy of driving the MS now won out. His new baby should be delivered in about a week and a half and he can hardly wait. He actually flew to the factory earlier this week in the hopes that he could catch a glimpse of it being built while on the tour. He's that excited.
We both decided to lease (we'd never leased before) so that in a few years it will be easy to slide into whatever new fun thing Tesla will offer at that time, and that seems like the best of both worlds to us. Joy now, AND joy later!
If it were me, I'd take the plunge and either lease or buy CPO! If you've driven MS and loved it, I can't imagine you'll regret it, no matter what comes next. Drool over new tech as it emerges? Probably, but surely no regrets. It's an amazing car and fun, fun, fun!