Most of top teams are rich, they won many leagues, they get sponsors and they can sign more strong players.
But mediocre teams that never become a champion will have a hard time to get sponsors, they can survive without accepting gambling sponsors, but they don't have money to buy good players, so there's a chance they could relegated to second tier leagues.
This is true. The level of sports we are seeing and enjoying at the moment are largely due to advertisement money involved. That is the money that translates to clubs and players. In this time of global sports, advertising is the only source of income for players, teams and organizers. The ticket price may cover the cost of keeping the stadium in order and nothing more.
If there were no gambling ads there would have been something else. The reason why gambling advertiser pay more for sports coverage is, all of its viewers are the target audience for sports betting. Personally, I don't listen to any pre-match, interval or post-match analysis. I get my info and stats from mobile apps. And I haven't encountered the commenter talk about gambling odds in mid play.