I think these are both great points. I don't think there is any actual quantitative research looking at the crossover between people who are into sports and people who consume anime and/or manga, that would be very niche research
Although, it would be very interesting to read about. However, just based on what I've seen in mainstream media and sports over the years (not scientific at all) - I'd say the overlap is definitely a lot bigger than what it used to be (either that, or people just feel more comfortable expressing their interest in it). After all, you only have to look at the most popular anime franchises to see that they do millions and millions worth of sales globally - I'm sure the stereotypical nerds can't be fuelling all of that industry, haha.
I think your second point is key though - are the people casually enjoying anime on Netflix/CR/in cinemas the same people who are collecting home video releases as well? Maybe, maybe not. Who knows?
I think this was definitely true in my experience when I was in secondary school. However, I'd like to think this has changed in recent years. There is a small handful of famous footballers who have expressed their love for anime on the pitch (either through goal celebrations or custom made anime football boots they wear) and on social media.
You can also look at Jamaal Williams who is an American running-back for the New Orleans Saints in the NFL: the man is publicly rocking Akatsuki cloaks/Naruto headbands and telling reporters he's "going home to play Pokemon".
I don't think you could imagine famous athletes publicly expressing their interest in something like that 20 or so years ago. Which I think does show the increased cultural penetration of the anime industry in recent years. I also think it shows a change in culture surrounding these interests, where people feel more comfortable expressing it.
The UK is its own individual case of course (what may work in France and the US, may not work in the UK), and Britain has definitely lagged behind countries like the US and France (
take a look at some of the anime TIFOs they have at French football stadiums), even Germany had anime on television in the 1970s. However, I'd like to think the UK is benefitting from the relatively recent increased popularity of anime and how mainstream it has become, in some way.
I guess what I'm trying to say is, give us some God damn sports anime, please Anime Limited.