They're adding features constantly, and they can
Elon believes that true FSD is worth a lot more than is currently being charged. This is a step toward equalization.
V10 added a lot of features that make it worth mode than previous versions.
Which features exactly?! The changelog says something about smart summon and nothing else?
Not even NoA has improved much.
And you had the basic summon which was practical and the smart summon is just "meh" for youtubers to test and not available outside of the US. This is barely worth 1000$ more the 2 times you are going to use it and fail (by the time the car comes you will walk, drive it out and get out)
The reason is simple - cause they can and people hyped it enough. If they see it will affect purchases, they will drop it again, but I doubt it. People belive anything Musk tells them and he is good at hyping and marketing, so why not grab extra 1000$...
You shouldn't expect robot taxis for at least 3-5 years and by that time most model 3 owners would've sold their vehicles or their leases ended.