I just thought of this, and I want you to view it from your own perspective. As everyone hopes that more people get to believe and use bitcoins, I think bitcoins can gain more new users on a large scale if anyone (whales ) can place their advert through a popular football club just as some companies do sponsor football league. I think this will send a strong message to billions of people across the world who do know but does not embrace Bitcoin usage.
Let me site another example, let's take for instance, a club announces that they will pay their players in BTC. This news can also help people adopt BTC.
Sponsorships for football clubs are in the order of tens of millions per year, and usually there are big companies behind it. Bitcoin is not a company, there is no CEO, there is no shareholders, the only way would be that someone who actually owns thousand of bitcoins decides to simply sacrifice part of his fortune, but it's highly unlikely.
Bitcoin is owned by no one, so someone spending millions just to make it famous won't benefit? That will never happen. Even if we ourselves are millionaires or rich by bitcoin, would we be willing to do it? I believe no one would be kind enough to do that so the idea makes no sense. Instead of coming up with grand ideas, if we really want bitcoin to become popular, let's do the simplest things. Like Marvel1 mentioned, why not mention bitcoin to the people around us first?