What's the connection between adverts and the amount of money Ghibli made on their best-loved movie?

Hmm, maybe none, maybe you're using Ghibli as a metaphor for products that make money through adverts. And maybe the implied answer to the next question is that their next movie, The Cat Returns, would have been higher quality if they had made even more money on Spirited Away. So what you could be saying is that crippling the ad industry would lead to lower quality products, without even much reducing the number of (less effective) adverts that get made.

That's one way to read what you said, but I feel like I got it wrong.