A simpler Tesla is conceivably a better Tesla.
I think this is why, from a manufacturing standpoint, many are surprised that Tesla's car options are getting more complex versus simpler. It makes more sense (to me at least) to simplify the line. Less parts to manage, less build options, and in the long run, less variables to worry about maintenance on. The line should be 70D, 90D and P90D (and I guess P90DL since I'm sure it's margins are sky high and good for profits).
Next year around this time the line should become 75D, 95D, and P95D (with variants). And so on and so on. It seems that instead of waiting on big battery improvements every few years, (going from the 85 to the 100, or 115) Tesla now will be shooting for smaller improvements every year.
I agree the 85 will vanish, but since it didn't today with the release of the 90, I don't think it will until next year at the earliest. Tesla likes to shake things up, but not that rapidly.
edit: The investor in me would have hated it, but they could have added the extra 5Kwh batteries to existing orders starting a few weeks ago and just snuck it into the line and bumped everyone up to 75 and 90's. Surprise! Right before the first deliveries made it to customers they release the news that all orders from June 25th on get the free upgrade. Then kill the 70 and 85 options all together.