What are we objectivists missing?

We're not missing anything. When I listen to a $99 DAC with a SINAD of 123, then switch to a $100 DAC with a SINAD of 122, I rest easy at night knowing that the $99 DAC is superior in every possible way in the universe.  Then I rush back online to see if that dreamy Amir has given one of my comments an upvote.

Subjectivists do have things going for them.

They do help to keep a lot of people in jobs for one.

Secondly they also help keep the used market thriving as they flit from one brand to another.

I should know, I was one.

For a while it was fun ride, but in the end it got tiring.

Audio for audiophiles is like golf for golf enthusiasts.  If you think there's a problem someone is willing to sell you a solution.  If you don't know there's a problem, someone is willing to invent one - and sell you the solution.  People have fun with either pastime attempting to invent perfection for themselves - which they'll never achieve but that's all part of the challenge.

Being an Audiophile is primarily about 2 things, your equipment and how it sounds. Each person is unique, what you hear is determined by your ears and your brain, what you enjoy is determined by your preferences and experience. I have frequently sat in a colleagues room or store demonstration room and listened whilst someone told me how great it sounded, but to me it sounded awful.  Long experience trying to like Klipsch or Cyrus electronics comes to mind (separate story told here more than once). I cannot say Klipsch speakers sound terrible, but I can say they do to me. You can measure them until the cows come home, they will still sound terrible to me. This pastime is all about finding an illusion,( the Beatles or Bach are not playing music in your lounge room tonight), that you like. Someone telling you that  a different illusion sounds better or measures better is completely pointless. Trying to be completely objective about something that is essentially subjective is not scientific.

@jtucker

"We don’t know what we don’t know"

Exactly. Our hearing acuity is much more complex than current science can define.

Not just cables but components as well. Great measurements can only get you so far, then the rest is an art of trying different things to improve the sonics. If we can measure what good sonics sound like, we’d have fatter bank accounts.