Re the "You can always switch it off (Or fast forward)" argument in support of Online concerts and the like....

Yes, you can whereas you can't do that in a club or concert.
However, many choose to go to the toilet or bar when a duff singer is performing or even if they know that there's a particular song coming up that they may not like. I've even done that myself, discreetly of course! :-)

Notwithstanding the above, it can be rewarding to persevere.
An artist may grow on you after a few songs and you might just be lucky enough to witness some classic moments and/or material. If you keep flicking through various You Tube clips and so on, you'll likely miss a lot and th focus is likely to be, for most people, on their favourite singers and musicians or those which have been recommended.

It's already the case that many younger people never listen to an album all the way through anymore and just pick and choose their favourite songs. That used to be one of the joys of playing vinyl and to a lesser extent actual CDs but all that has been lost.
I'd hate things to go the same way with live performances and concerts.