It is too bad that early adopters got screwed with high flying promises. Those AP promises were made when Tesla used Mobileye. As we all know Mobileye got kicked out in 2016 and Tesla had to essentially start from scratch to develop EAP...on their own.
That is why those lofty goals fell apart. Sad but that is life.
Completely self-inflicted wound as Elon was planning to rip off Mobileye IP (they built AP2 with both Nvidia GPUs and Mobileye, intending for Mobileye chips to train their own neural networks so that Mobileye will no longer be required). Also, nothing was stopping Tesla from continuing to complete their promises for AP1, except maybe lack of sensors or forethought what it would actually require to achieve their promises.
Secondly, AP promises are not the only ones that early adopters got burned on. 691hp for P85D? Another one of Elon's dreams he couldn't make happen (well, he did eventually for P100D, but it took different hardware Tesla was not about to upgrade the P85D owners to). Those who purchased P85D over 85D paid $25K extra for what they thought was 315 additional hp (691 vs 376), what they got was 46hp (463 vs 417) and an excuse that the car is capable, but not the drive-train or the battery. How about the SDK they promised, again nothing to do with Mobileye. And now they broke the browser too, so can't run much at all on this large screen anymore.
I recently got my Model S 100D for a lot more money than earlier Teslas, but I was content that in worst case whatever features I got were the only features I ever see. And if the car actually improves with OTAs, that would be a bonus.
I would settle for my car not getting worse with updates. Over the years it has slowed down, browser stopped working recently almost completely (couldn't even load google search for "Tesla" earlier today, LTE showed full bars, then again on full bars WiFi), WiFi connectivity further deteriorates (it was very fragile to begins with, check stories here in TMC how hard it is to keep a Tesla connected to WiFi, but after MCU2 got released MCU1 got even more wifi problems, I recently tracked it to for some reason MCU1 makes the Access Point think it has 5GHz capabilities, while it lacks the hardware of MCU2).
I wish Elon and Tesla would focus on making a better car for the driver, rather than on Elons hot air. Instead of adding Atari games to the car, make your wifi more reliable, fix stupid things like the car generating a warning every time you get out of the car with lights on - the lights go off no problem, but the car makes identical warning noise to the one emitted if you attempt to leave the car while still in Drive (the messages says the car's range will be reduced because lights are on, but it won't because the lights go off as soon as you get up from the seat) - that bug has been there since 2013. They have recently done some useful things, like enable update installation from the app, but at the same time, after the app update couple of days ago my Android phone has problems connecting to MCU2 car (not yet on .39) white it connects fine with the MCU1. Lack of consistent reliability and feature/use-case polish is what Tesla focus on fixing, instead of easter eggs.
The software is now improving by leaps and bounds...mostly for HW2x, HW1 is however screwed(that hardware is too limited).
Aha! Here is your biggest drawback of over the air updates. They sell you vapourware, and you only get whatever they release by the time they get new hardware, leaving you screwed, as you say. AP2 owners will get just as screwed when AP3 comes out, as they'll get only whatever happens to be done by that time, anything else Tesla will go radio silence on.