Well, then, it's just a matter of what it's worth to each of us. And I fully agree that as a post-purchase option it should belong to the user, not the car. I'm not rich. The whole Tesla purchase is a stretch financially, but I'm already in.
I had EAP, which means I already had everything the automation does right now. THAT costing $5k was unquestionably worth every penny to me.
On the "FSD" option (and I understand that to mean incrementally self-driving) I wasn't biting at $6k more, because that meant $11k total. Musk got it and offered it to us at $3k, or $8k total. So I was OK to add that $3k, to get the 3.X hardware and the features that will go with it for years. And I believe that other EAP owners would also do well to take advantage of that $3k offer.
=== What about non-EAP folks? =====
Now, for people that have the basic AP/AS/TACC - that Tesla maybe too generously included in the base model - adding $6k to add, at the moment, "only" NOA, Park and Summon may look high. But a total $6k for all M3 automation present and future is a no-brainer. It's even $2k less than what I paid.
If I were buying another Model 3 or Y, personally I wouldn't dream of splurging on dual motors, some extra range, Performance, plastic wraps or clear bras, but I wouldn't dream of not adding the full automation, the "FSD" package. A monster vehicle at $45k.
Why? Because after weeks learning to use NOA effectively, it's something I now use every day to advantage. And looking at the rate at which the NOA and Summon and Self-Park have evolved since December 2018, I extrapolate and conclude that I do want everything that comes next in the next year or two or five. Your extrapolation may vary.
To someone who's only "given it a try" and has been put off by shortcomings, it may not be instantly convincing. You'll be back. To someone on a short-term lease, or someone who's a devoted gearhead manual driver, it may not be worth it at all. An SR+ (with a third party $100 subwoofer) is a phenomenal value at $39k, and a remarkable car. Peace.
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p.s. As to why Musk included as much AP in the base models, I think it's to honor his promise of a $35k smart EV. Hats off to him.