Yes but I found the definition I gave much more helpful to explain to people as an starting point, in one sentence or two. It helps dispel the relationship with happiness, (in)ability to change and other false dichotomies.
OK but you're skipping over the central point that the energy drain disappears as a person grows more "skilled" in extroversion. You're welcome to disagree, but your comment is closer to ignoring the entire debate than addressing it :)
I'm not sure that's true. There are alternative possibilities: That one learns to predict (some kinds of) people. That one's obsessed with a series of topics that gets oneself bored when not being able to discuss, etc. There's many, many small reasons an introvert's energy is depleted, that is not just "being with people".
As an anecdotal data point, I was very introvert and I did learn to "be extrovert" and many people wouldn't notice at all, but at the end of the day I need to be alone, sometimes for days to recover and be productive again.
Even though it's anecdotal I think we can't generalize and say "introversion doesn't exist". There's a lot of factors involved. Stuff may be even more complex when dealing with an ASD.