There are no ads on Stadia nor have they announced that there would be. You currently have to pay full price for their games, I don't see how you can just shove ads into them.
Maybe in the future if they offer a subscription but right now your comment is just guessing at the future intent of a newly launched product.
Maybe in the future if they offer a subscription but right now your comment is just guessing at the future intent of a newly launched product.