I'm going forward. The current model 3 has the range I need, and a price I can afford. And if in 7-10 years or whenever the day I need a new battery arrives and I find out there is a much cheaper replacement one available... Hooray for me! Musk says a new battery is in the 5-7k range for me cost-wise. If I can save $2500-3500 in 7 years on that, sweet.
Battery day in September will have some really cool news. Just like Autonomy Day last year promised 1 million robo-taxi's by the end of 2020 on the road (4 months with just 1 million left to go, and a bit behind the other 2017 promise). My guess is we won't see the roadster deliveries this year either.
No offense to Tesla and Musk so please don't take it this way but when it comes to many things, such as the performance of the vehicle, he understates and over-delivers. When it comes to producing and manufacturing a product on time.... well there's a little learning curve there.
In the end it's technology. The next iteration of your phone is only a year away... Every single year. The next iteration of your laptop is only a year away... every single year. You can wait for the cool camera, but then you are just a year away from the wireless charging, but then only a year till you get the facial recognition to unlock it.
That happens with cars too. A LOT. Oooh next year they are getting a new motor with X more HP, or next year they are giving it a new safety suite with adaptive cruise, or next years model is getting this redesign... In the end, Tesla covers for a lot of that with it's over the air updates, but they will always have a cool new feature just around the corner to get you to trade in and buy new. You don't have to buy the new model to get sentry mode for example. It's part of what sold me, a buddy said he doesn't feel left behind like his phone even though he got one of the first model 3's a couple years ago.
Also... sure, in 2024 I might be able to get a model 3 with a longer lasting pack and save $4000 on the price. But what will the FSD cost be at that point? Or will they be putting it into a true mass market low budget hatch and the Cybertruck, and not be integrating it into the Model 3 until a 2026 refresh?
Just my 2 cents.