Yes. The transfer of “Free unlimited supercharging” included with an older model is a completely different issue. Not that the general public should know all these details that many on these forums do, but your post is confusing because it’s conflating a number of issues/features/situations and therefore hard to answer definitively without more details.
In case you care to understand: your post title sounds to many of us like what many have complained about not being able to transfer FSD Capability package or EAP on a Tesla we own to a new Tesla we buy now. That’s the question
@Dewg was answering.
Then there’s also the issue of private party sales of Teslas with FSD Capability package or EAP. If ownership ever passes through Tesla (like some at used car dealerships), then FSD Capability package or EAP is usually stripped/removed when a new owner transfers to their Tesla account (i.e. - takes ownership). If sold directly and never passes through Tesla (i.e. - ownership account switches directly from seller that had FSD Capability package to buyer of said Tesla), then the software package isn’t stripped/removed. That’s the question
@jjrandorin was answering.
The whole mention of Tesla solar was very confusing to me (and probably others). But with more context you added later it’s more understandable why you’re bringing that up (and no you don’t want to give someone your Tesla account because yes they would own whatever other products are on that account, or maybe there’s the complicated workaround if just one car and solar that you could transfer ownership of the solar to a newly created account and then give the buyer your old Tesla account? But seems risky and not advised).
Then you brought up free unlimited supercharging which is a completely unrelated situation in regards to transferability.