If they fully manage to block applications from viewing YouTube, then I will just stop viewing YouTube entirely. And I will figure out channels to watch on Odyssey and peertube. That will also be my last Google service since that is the only one I use frequently since I deleted my Google account two years ago.
Sounds great in theory, but won't happen. The internet is too consolidated now for the majority of people to give a shit, there's people buying YouTube Premium because of all this. Look at reddit, barely a dent in it after all the fiascos, twitter is holding on too. People don't care.
At the scale youtube does things it doesn't really cost them much. They actually have the servers, the bandwidth, often the power. It's not like they get to sell a server if enough people leave. The savings probably do not even justify the effort (=cost) to unplug the server. And they still get many other benefits of having you as a user (getting to profile you, getting to push propaganda, getting to sell your information, maybe you send videos to friends who don't use adblock, maybe you buy merch from creators making creators happier on their platform).
On the other hand this enshittification is ruining their monopoly, other areas of business (if you don't need youtube, maybe you don't need a chromecast? If you don't need a chromecast, would you buy pixel phone, that can only do chromecast if samsung can do hdmi? Maybe you're done with android? And if you're on iphone, are you still using google maps, photos, search, keep etc?) and curing people who are addicted to the platform.
The eventual consequence of enshittification is always platform death. Which would be amazing, sadly the next platform is going to repeat the cycle.
At their scale and cost optimization it's likely one of the few remaining holes to plug. I wouldn't underestimate how many people try to block YouTube ads which adds up quickly. Whatever the benefit is from allowing people to keep draining their resources, it probably doesn't outweigh benefits in the non-0% interest rate environment. Their monopoly is also nowhere near threatened and their biggest competitor could be banned in the US.