The difference in sound quality between a .flac and 320 .mp3 is imperceptible to the majority of people and needs thousands of dollars of listening equipment to become apparent.

I would disagree with this. It isn't really a matter of equipment cost. It may be a matter of not having ever heard a direct comparison between versions of the same track, though.

What I've noticed is that you really need e.g. wired headphones to be able to hear this difference. The compression artifacts of MP3 are quite distinct, but since Bluetooth tends to compress audio as well, this eliminates a lot of the difference between lossy and lossless sources.

I can hear the difference clearly with cheap (≈$50) wired headphones on my android phone (which is nothing special and a few years old). It is particularly noticeable with high frequency sounds, like hi-hats, which tend to sound muddy with a kind of digital sizzle.