More time spent implies more ads shown implies proportional conversion.

Also now that we have two big companies vying for attention, the competition is fierce to show "relevant ads" first because both receive intent almost simultaneously.

I got a youtube short of an office chair company in the feed. I wasn't looking for it explicitly. It was organic feed. Almost immediately I got an ad for that same chair in gmail. Because all of our phones are always listening for intents and keywords. This is recursive ad slop.