@Thad
You are so dead against hi-res...
I'm dead against marketing bull (but aware that, of course, I fall for it too!) and ...I have those, err,
ranting days. Seems yesterday was a day for a good rant

hyeah:. Which isn't to say I don't still believe it today!
As for how against "high-res" I am, well, as I mentioned earlier, I
bought some the other day with high-res dollars

. Apart from that, I'm just like everybody else, reading the viewpoints, trying to understand the theory, weighing it up ...and yes, in so far as my equipment goes,
listening to it as well. Did I say "everybody?" OK, I meant everybody who is not simply taken in by some marketing gumph with
bigger numbers in it. OK, not everybody; not even close

.
This site does support you in your
crusade and it nicely concludes that there are no major benefits of 24 vs 16...
Probably the most crusading (and largely unpopular) reference is
the xiph stuff.
... except that
1. It helps in recording by giving enough headroom and help reduce quantization errors in ADC process.
True.
In the pro world this debate has been settled, almost everybody is recording with 24 bits today.
They have some very good reasons to do so.
And headroom is the real reason why recording engineers work at higher bit rates. It has nothing to do with there being any advantage in them to the end listener. To claim or imply otherwise is simply misunderstanding the process.
2. It helps in digital volume attenuation since more bit depth= less % loss of bits
True. But audiophiles hate digital volume control! Theoretically, they have good reason, and I think most of us try to avoid it, even though, in practice, it is actually quite usable.
3. Dynamic range improves so we hear sound close to the noise floor more clearly in 24 than that of 16, subject to the limitation of the DAC (SNR).
People write stuff like, "I did xyz and the noise floor got lower," but... the noise floor is
waaaay below our hearing, so I wonder at it, just as I wonder at that claim. To be fair, I also wonder how much stuff that we can't hear affects stuff that we can.
4. Decay of instruments are better heard in case of 24 bit subject to DAC performance.
If 16 bits is sufficient, it is sufficient. I can't argue with this one, but if it is true, then surely something is wrong!
If it is true that, with 16/44 pcm, the wave form you get out is the wave for that was put in, then all the claims for higher rates are wrong, or, at least talking about stuff that is unnecessary.
Maybe, for stuff to get really better, we have to wait for
something completely different. DSD? Is that hype too? I have no idea: for me, it is, as yet, a vague dot on the horizon.