I have a child with AuDHD who has trouble masking consistently. That coupled with impulse control issues and an inability to regulate between the two just looks like chronic deception, lying for the sake of lying. It is exhausting for him and it never works in his favor. We spend a lot of effort coaching him to not mask and to not seek unearned attention, and its a huge challenge.
There is a death by a thousand papercuts situation with being disabled where you will have to explain yourself dozens of times a day and you get stuck with having only one conversation subject with any given stranger you meet.
For some people, masking is just an easier, freer form of existence. It's like asking for a dressed up coke at a happy hour so your coworkers wont grill you about abstaining from alcohol. Or how people who work in callcenters seem to converge on a way of speaking that makes the interactions a little easier.
It's just that for autistic individuals, they are highly analytical about how everyday social interactions work and doing this costs them more cognitive load than you would expect.
I completely understand why people do it. My point is to pick your battles well. There are many cases where masking brings far greater pain than return on investment. When masking does fail people see right through it AND the thing you were attempting to hide is now exposed in great glorious fashion when like a Striesand Effect.
Masking is a learned behavior - learned specifically because the person in question had sufficiently unpleasant experiences being unmasked that they decided they needed to try hard to mask in order to avoid said unpleasant experience.
No one masks at birth. If you want your child to stop masking, perhaps it’s helpful to investigate what caused them to learn the behavior in the first place and what could be done to make the experience of being unmasked more pleasant and less aversive for him.
Just as you say, masking takes an incredible amount of energy and is exhausting and often backfires. Why would anyone expend such exhausting amounts of energy without some extremely strong motivating factor? The alternative to not masking must be perceived as exquisitely undesirable.
I think people think masking is just for those who have Autism. I think at some level all people mask. Most people behave differently outside of work or in public places when they are alone or with close friends.
I think with Autism the process of masking is just harder, and the ability to read social queues takes extreme focus to understand the general emotional state of others around them.
Does that example really require masking? Absolute not. You don't have to lie when you provide a neutral response. Examples: "Busy day", "Just feeling tired", "Many things to get done.". Those are not necessarily good or bad and suggest you aren't making small talk.
Or, if you provide a never ending story they will see your disability for what it is and they won't ask you a second time.
I'd say that's not masking, since literally everyone does it. As a famous comedian that I can't quite place right now once said, (paraphrasing) "the only valid answers to "how are you doing?" are good, fine, or okay.
Honestly, some things like this are solved with learning certain skills, practicing them a bit, and then it becoming easier. Answering to "How are you doing?" does not require masking, people asking it in casual contexts usually do not expect any kind of "honest answer". It is as hard as answering "hi" to "hi". There are plenty neutral answers that neither require you to smile and play it happy, not invite some long, awkward conversation. It could also depend on where you live though, of course.
I have a child with AuDHD who has trouble masking consistently. That coupled with impulse control issues and an inability to regulate between the two just looks like chronic deception, lying for the sake of lying. It is exhausting for him and it never works in his favor. We spend a lot of effort coaching him to not mask and to not seek unearned attention, and its a huge challenge.