Side-note: I couldn't load the game in Safari (which has amazingly poor WebGL support).
One successful path seems to be early access on the web to build a following, with a release on Steam/app stores for monetization afterward using Electron or Node, with the web version remaining as a free demo (e.g. Vampire Survivors or CrossCode). The other path is ad monetization, and there are a lot of portals like crazygames.com or poki.com that host that type of game. I think the market there is largely schoolkids with Chromebooks. I'm not aware of any successful web games that are sold as an up front purchase like Steam games.
I don't think traditional AAA makes sense in the browser right now, but I see all sorts of UGC experiences having large synergy with web standards. The business playbook is largely there too.
One reason the market isn't sufficiently large yet is really because of the creation tools at our disposal imo. Web 2.0 explosion was arguably driven by great network effects of the proliferation of mobile cameras.
Right now, none of my friends make 3D content. I personally believe that's going to change with depth sensors, 3D scanning, nerf, generative content, etc.. so the trendline is there for me to buy this theory. I'd look more towards social games, hangout type experiences, or async consumption... as opposed to realtime, networked, embodied, immersive.
Side-note: Apple has demonstrated the willingness to change their tune on WebGL, I suspect they'll catch up pretty quick.