With you tube being a streaming service, they tend to normalise all audio to a perceived loudness of -14 or -16 LUFS - i.e. it gets multiband audio and digital compression so it'll never sound as good as a lossless version. Though as most folks don't listen back on decent kit they'd never know the difference.
Not sure what this means! Back in the days of NICAM I used to take mixes home to check for rumble missed by the Rogers LS5/8 monitors they used to use... Nowadays all TV is delivered as part of a AS11 DPP file with the audio component being a 16bit wav at 48kHz, bandwidth 20-20kHz with a max true peak of -1dBTP, and max perceived loudness of -23LUFS so in theory pretty high quality, and they use Harbeth 40s which are far better.
It was true that in the days of live TOTP'n'all that there was a breed of studio sound mixer (I was post production) who didn't believe in enhancing in any way, it was basically as it came, warts and all, not even reverb on vox - later trainee intakes emphasised creativity over engineering and scientific knowledge, so things have got better! However, with BBC training having disappeared largely all they have to go on is required tech specs.Radio ones here, but they're basically the same as for TV, https://www.readkong.com/page/audio-quality-information-standards-for-4418233