Nitpick: while I agree that “full self driving” is kind of a promise and that all those charges should be reversible, you still get immediate feature unlocks today immediately after paying for it, like navigate on autopilot/smart summon.
So... turn those off again, then.
And clothes have another dimension (heh, literally) of size/fit/feel. I think it's totally reasonable to buy a shirt online, put it on, think "wow this material is awful" and return it. That's what you can do in-store, and it's not your fault that that loop is a lot more expensive for online retailers.
Free returns are usually a requirement for clothing sales though. Say, Zalando has free returns within 100 days -- people expect this as clothes obviously need to fit.
Say unlocking Boost Mode costs $2k. What would the subscription cost, $200/mo?
If I can show off Boost Mode to all my friends in one month, I might never care to pay for it again after that.
If my only way to get the feature is a permanent unlock (and I can afford it), Tesla scores an extra $1800.
Subscriptions work for sticky things. Are Tesla's add-ons all that sticky?
I don't know.
But that doesn't seem very relevant. Tesla has already shown they will upgrade customers who have purchased full self driving to their latest hardware package (v2 -> v3).
He also says there is another generation of hardware in the works. Not sure where that fits in. But if they can roll out a 2.5 -> 3.0 hardware upgrade, as they are doing, I don’t see what prevents them from doing that for 3.0 -> 4.0 hardware when the time comes.
Although I don’t know where that fits in, I do know where it does not fit in, which is into a made up narrative which falsely claims that Elon promised the hardware would never change and never be upgraded.
I realize that’s not quite in the spirit of your question but I’m also pointing out that the question may be moot.
Also the qualifier “major” is up for discussion. A replacement of the main computer motherboard certainly seems major on its face, but if it can be done by a mobile service tech in half an hour at a location of your choosing without you even needing to be there, then it’s not so major, in an important sense.