They might to an extent, but I don't think it's required or necessary. Ads can go on any type of videos, and if Youtube had less traffic as a result of less clickbait, then presumably the costs to host it would be a lot less too.

Apart from this, keep in mind that Youtube TV likely pulls in a ton more money, and even if it didn't, Google/Alphabet has many other larger sources of revenue that could pay for Youtube too.