I don't think that "audiophile" ethernet switches prioritize certain packages over others. As you've already explained, that's technically not possible anyway.
It is my understanding that those things are (supposedly) made up of somewhat higher-grade components to reduce chances for packet loss, i.e. "better" power supply, "better" circuit board layout to reduce sources for noise, "better" internal shielding, "better" connectors, etc.
Anyone with even just a cursory understanding of how TCP/IP works knows that that's all just a pile of marketing manure. Packages are packages, and if one gets lost along the way, the TCP/IP stack will take note and request for it to be resent.
If your home network works fine on your average bottom shelf routers and switches, it'll work well enough for all your audiophile needs.
But at this point in my "audiophile career," I don't really mind all this audiophile marketing spiel anymore. This is a hobby that's virtually crawling with people who have way more cash at hand than they could ever possibly need for themselves and their families. And if they want to use some of that disposable coin to pay for some dude's kid's college fund so that they can tell themselves that their system sounds better? Then by all means; be my guest.
I'd prefer to live in a world where honesty in marketing prevails. But I also want a world at peace, run by a socio-economical, self-governing system that works without money and is driven by each individual's personal, innate, self-motivated drive to add net-positive value to the human experience and the planet as a whole. So there's probably something terribly wrong with my brain.
Let them have it, I say. It's not like debating people on these topics would lead to any actually positive outcome. All I can do is to make and market products that actually do what it says on the label, and without up-charging well-meaning but gullible hobbyists falling for a bunch of smart-sounding technobabble in the product description.
PS:
I'm not cynical,
you are cynical!