The Sennheiser HE-1 doesn’t lack features that the competition offers. It actually offers more than the competition as it is a complete system where the DAC + amplifier and headphones are carefully designed to work with one an other without zero compromise.
I have heard many different headphones (including from Abyss, Susvara, SR-009, Utopia, ....), and the HE-1 is the best so far. And despite this, the Sennheiser HE-1 gets flack also.
Problem with the Airpods Max, it does not offer more than the competition at the higher price it offers, it offers less.
Similar to your thoughts on the APM, that's subjective as well on the HE 1. The Senns don't offer more than the competition because other competitors including Sennheiser themselves offer a complete system. You should know that if you really were into headphones. The only difference is that the HE 1 offers opulence. Which it does achieve.
So at $50,000 and not even being voted as the best audiophile headphone, it does offer less in terms of comfort and sound quality. Again that's subjective. Same as what you are expecting from a measly $550 wireless headphone to "out do" the competition when Apple isn't even trying to compete as well.
If they did want to compete, they would have priced the headphone at $350. If they wanted to compete with a desktop, they would have priced the Mac Pro at $3,000. It doesn't mean they delivered a better experience because, again, that's subjective. It just means they're delivering a DIFFERENT experience which only people baked into their ecosystem would appreciate.