My first thought upon hearing this was "oh, I guess my time lost to youtube-dl + mpv of those few channels I have bookmarked will finally be reclaimed!" (assuming this breaks it)
This move makes zero sense on their part. Cutting off your addicts is a horrible approach to being a drug dealer. You always keep them hooked to your supply, if you wholly interrupt it they'll quickly seek replacement. That's literally what created the illicit opioid crisis - folks lost their prescription opioids and immediately pivoted to street dealers.
Surely youtube has better options than outright blocking users of adblockers... Why wouldn't you first just restrict the quality of videos they can access to extremely low-res. It lessens the bandwidth burden on you, and may be enough to keep them under your spell and away from the competitors supply.
There's far too many people in "business" today who think they provide anything of any real, determinable value to me rather then a passing fancy which will be easily replaced or discarded.
And this doesn't just apply to the content hosters: it also applies to their advertisers. There is nothing of value being advertised these days. It's all misrepresented junk, when it's not outright scams. It isn't worth ever exposing yourself to.