Does it really, though?

When I look at the [url=https://en.wikipedia.org/wiki/2025_Australian_Open_%E2%80%93_Men%27s_singles]Men's Singles[/url] and [url=https://en.wikipedia.org/wiki/2025_Australian_Open_%E2%80%93_Women%27s_singles]Women's Singles[/url] main draws, I see a wide variety of nationalities represented (many from Europe, but also a decent number from Asia, Australia, and the Americas - and even a few from Africa). And the recent winners of women's Grand Slams have a very wide geographical spread (admittedly, that's less true on the men's side, but that's mainly because of the sheer dominance of the Big Three in recent years!). 

So, IMO, tennis doesn't have a diversity problem: the only region that's noticeably underrepresented is Africa, and even that's easily explainable by economics.