I would disagree - selling it as a service implies all updates would be available to subscribers. It would make no sense otherwise. When you subscribe to Netflix, do you only have access to the movies that were available the day you subscribed?
that’s not what I was saying.
My point is that when you buy fsd in 2016, you are entitled to all updates required to make fsd work and entitled to actual full self driving, meaning new hardware and software for as long as you own the car.
With the subscription model, you are only entitled to the features available while you are subscribing. EG, if you subscribe to FSD in 2021 you only get features and hardware available now asks no future liability exists for Tesla to deliver full fsd.
If you get tired of waiting and cancel your subscription you are entitled to no hardware or fsd software updates in the future. Unlike the case if you bought fsd outright.
In addition because you are purchasing a monthly liscense if it turns out fsd requires additional hardware your car does not have, under the subscription model Tesla is not obligated to provide it even if you are a current subscriber. All they would need to do is say the subscription is no longer available for your car.