I think it's too early to truly tell. There'll always be a future demand for electric, because the industry is full steam ahead. That being said, since it's just the beginning, I feel there will actually be a large market for used, non-2.0 models.
I personally think we're still a good 2-3 years away from 2.0 being the standard. Mostly due to the regulations, and partly due to consumer fear & acceptance. Those that HAVE to have fully autonomous 2.0 and beyond are a small sample pool. Those who want it, slightly larger pool, and those who will just wait till it's as common as a factory option on a Corolla are the largest.
Seemingly from what I've read, 2020-2021 is the general consensus for the "we're fully autonomous, too" as far as the rest of the industry is concerned. Tesla is just far, far (as far as implementation and experience) ahead, which in theory they always have been since they started.
Point: a used 2012 Model S will still be worth a decent amount of money in a few years. Comparatively, to a 2012 5-Series/7-Series BMW, E or S Class Mercedes, etc. (which are further and deeper into ICE-past) the Tesla will be worth FAR more. Why? There's a broader market. Before I bought my 2016, I was seriously looking at a 2012 S base model for $48K and was excited at the OPPORTUNITY to even be close to purchasing a Tesla in-general. More and more people are realizing what a Tesla is, who they area, and the desire that comes with that. AP 1.0 or 2.0, the used market is opening wider and wider every day. Then it comes down to the ol' principals of supply and demand.
Cliffs Notes:
-2.0 won't tank values of 1.0 equipped models.
-Tesla now has a used-vehicle market which it did not have previously.
-Used ICE vehicles will become less and less sought after, further reinforcing Tesla's used market.
-Supply and demand for a used Tesla will dictate it's value.
-Tesla rules.