You're so right. it's not an if anymore, but when. and when it does, you wouldn't know what's an ad and what isn't.
In recent years i started noticing a correlation between alcohol consumption and movies. I couldn't help but notice how many of the movies I've seen in the past few years promote alcohol and try to correlate it with the good times. how many of these are paid promotions? I don't know.
and now, after noticing, this every movie that involves alcohol has become distasteful for me mostly because it casts a shadow on the negative side of alcohol consumption.
I can see how ads in an LLM can go the same route, deeply embedded in the content and indistinguishable from everything else.