"most can't and won't take advantage" of it is a broad statement. i would think there are a lot more DAC/lighting adapters and analog headphones in the world than there are of AirPods, anyone that wants to listen to CD (16/44) quality can probably do so for free or a few $ already. my home "hi-fi" now consists of an old iPhone 8+ hooked up to a DAC piped into my receiver utilizing 24/96 setting from iTunes, no longer need for Tidal or Qobuz.

This is true for wired headphones, definitely. My statement was broad, but was aimed at wireless headphones, apologies for the confusion

With high enough “resolution” does it really matter? (Don’t trying to start a fight, genuinely curious as I’m not too well versed in audio)

We don’t cry over bitmaps vs vector graphics in most contexts, especially that the hardware is trivially limited. It’s probably a bit more nuanced with speakers, but I imagine that they also have very real limits on distinguishable outputs for a given input, even if it is not as trivial to see as in the case of a w*h pixel grid of depth n.

Short answer, no.

It might be possible that with very ($1000+) high end headphones about 5% of people could tell a difference, but even that is questionable. I have done many blind A/B tests with my $500+ headphone setup and no one has ever been able to accurately tell the difference repeatedly. There is absolutely no way that someone would be able to discern the sound difference between 320 and lossless on an AirPod-quality speaker.

I’m not sure about large speakers however. I assume that it’s equally difficult to tell any difference, and I couldn’t when I tested my setup. However, I have listened to some incredible $4000+ speakers before, and at that level I wouldn’t be surprised if differences emerged.

There’s so much snake oil in audio and placebo can effect sonic perception so heavily that it’s nearly impossible to find anything objective. There’s also a lot in the chain - the DAC, the AMP, room acoustics… that will effect the sound, sometimes substantially - let alone the speakers and the actual source.

While microphones obviously exist, you can’t measure sound the same way that you can measure the nits and white point of a monitor - it’s far more intangible.

There is a significant difference in quality between my Slim Buds with LDAC support and my One Plus Buds without it.

It does to some - I recently rediscovered my love of CD's and was surprised to find they sounded much better than I remembered - I am currently in the process of upgrading my music to CD quality and higher, and was equally surprised to find that Apple doesnt support a hi-res codec for their wireless headphones, even though they offer hi-res music. For me, it makes their $549 (!!!) AirPod Max product extremely confusing, laughable even.

So yes, I think mp3/aac to CD, the change is very noticable. CD to HD (24bit), not so much

Using lossless audio with AirPods is still preferable. Rather than re-encoding a lossy stream with another lossy codec, you only encode it once. Is it minor? Yeah. Can I actually hear it on AirPods? No. But it's not entirely moot.

This is true. It's better than nothing, but the price they are asking for ($549) for a top tier headset that CANT do hi-res audio is offensive if you know what you are looking for.