therealduckofdeath :
Mac_angel, I have plenty of 24-bit FLAC music. Places like 7digital or Qobuz actually sell that these days. If you want to review a review on the little details, you need to get the corrections right.
Can I, personally, hear a difference between my 16-bit FLAC and 24-bit FLAC? Probably not. Maybe if I had been 20 years younger...
I knew that "FLAC" was going to come back on me. It was already a long enough rant that I didn't really want to go into more. FLAC is just an uncompressed audio file. It really depends on the source, which can be anywhere from a crappy 8bit recording to a 24bit, 384kHz or greater. Many enthusiasts will say that high res will be uncompressed 24bit/192kHz or greater, though there are sites that offer 24bit vinyl rips, claiming they are high res, and so many other variants. As I mentioned, there really does need to be a standard put in place.
Your age is probably close to mine, though no need to post them or anything. Yes, as we get older, our frequency bandwidth shrinks. But high res audio isn't just about going really high and really low, it's about having more "information". And you definitely need the right equipment to be able to hear the difference. And, regardless of age, you can still train your ears to hear the difference more and more. I remember when I first got the headphones, I had already started collecting high res music. I listened to "Hotel California", first on MP3, and then on high res FLAC. Turned off the lights, laid in bed, eyes closed and just listened. There was so much more that you could hear in the high res that you couldn't with the MP3, and it was a good MP3 rip. Now, yes, you can mention that I'm talking about far ends of the spectrum, but I'm also talking about listening to them the first time, and the headphones not even being broken in yet. My appreciation has grown since then.
I can't say for the sites you listed specifically, but I do know that there are a lot of sites that are selling/streaming "high res" FLAC audio, but when tested, they turn out to be upsampled from a regular 16bit/44.1kHz. Much the same way as a lot of projectors now are claiming they are 4k, but just means they take a 4k signal, but not really display proper 4k resolution.