I agree.
But to come at it from a different angle...
I've got ADHD and Dyspraxia. My ADHD affected me badly as a kid due to my poor emotional regulation (was removed from mainstream education for a few years for doing things like stabbing other kids with pens and hitting them over the head with objects, always bully types or older kids). Just mentioning that to be clear I'm not one of the people who mostly got through life ok and was diagnosed as an adult when relatively stable. I was pretty wild as a youth.
However, I'm only just past 30 now and doing great, despite really struggling in an office environment in my 20s. Most dyspraxic people struggle with driving cars but I drive trucks and heavy plant almost daily, often around city centres. Although I might take longer to grasp most physical skills I don't seem any worse than most people once the pathways are developed. In many cases I'm well above average which I put down to being quite analytical and competitive and never being complacent which is mostly just a product of being restless all the time.
Made almost £60k last year and have zero debts so don't think I'd feel justified claiming PIP because I just don't need it. But I'd probs be able to give it a fair shot if I wanted with it not being means tested. I believe ADHD alone is a 43% success rate but with a comorbid condition the chances can be much higher.
I reckon a lot of people in my position would give it a punt - I've defo had a few suggest it to me. But tbh I don't even tell employers nowadays and only my friends know. I feel I'd be taking the piss if I were to try and claim and it's not whether anybody else knew. It's more a matter of principle.