Hearing also degrades over time. In my 20s I was a lot more fussy about audio formats and hi-fi gear.

Approaching 50, with less sensitive ears and a bit of tinnitus, I’m happy with the convenience of Bluetooth headphones and whatever format Spotify uses.

I did this with a japanese punk band and when I finally got on a private tracker, I redownloaded them and the quality difference was night and day. I have a huge backlog of mid-grade MP3s from TPB back in the day and I'll occasionally download a second flac version of the albums just to get the dynamic range.

Opus - perhaps, but claiming that 128kbps Vorbis is transparent would be rather stretching it (unless it's a mono stream); though how easily it will be detectable depends on the kind of music used to test it. However, if you added, say, Bluetooth A2DP to the mix and made it go through a lossy encoder again the difference should be pretty obvious to anyone with good ears.

I can't tell the difference with most headphones, but with monitors or a good system in a good listening environment there are some details that get lost in compression, but there's essentially 0 difference from losslezd if I rip a CD to opus or mp3 rather than from a stream.

Properly encoded Vorbis, Opus or AAC (even Musepack) certainly reach transparency very quick, but who knows what horrible sources were used on non-official YT music? And what dismal remasters?

crappy speakers?

Yeah, but people aren’t uploading high quality music to begin with. It’s probably like two or three levels of compressed by the time you yt-dlp it.