>"It really is incredible that they would run these finals on the live internet."
I think they were thinking in terms of doing in-person physical LAN versions, and as another reply said that's a not insignificant undertaking in terms of cost (if nothing else, just plain having potential competitors from all over make their way there), though given all the amateur traditional sports that manage it for everything from surfing to dogsledding I'm a little skeptical that it'd be that impossible for these companies. But yeah it's a jump.
However, I do wonder if there's ever been any consideration to using VPNs to that end, at least for the finals? Have players set up a WG tunnel to the mothership with all other networking disabled just for the match, that'd be about as good and if it was super easy seems like players could be onboard for it as well. It wouldn't be some big interfering kernel thing like so much anti-cheat, not anti-cheat at all in fact just security against external griefing, they could turn it right off after. Given this is clearly unusual maybe not something to worry about in general, but could be an approach if it proves a bigger problem.