The Web is basically just a runtime you don't have to host your files on a server if you don't want. You can distribute them via CDs if you prefer. Also you can use Service Workers now.
That said monetisation all depends on the product not the medium. Just look at Minecraft. It didn't use ads or microtransactions and yet it was run from a Java applet in a browser.
Framerates aren't the same, memory usage isn't the same, and you can't easily tweak these things once they've come out the other end. The web _isn't_ just a runtime. It's abstracted like that, but browsers are glorified HTML renders with JavaScript bindings, event handling, and sound and video playback to game developers.
HN has a subset of the community constantly raving about these things for game developers, but where are the game developers actually praising these things? I don't know of any, personally. We're all too busy with desktop games.
[0] Mind you, said order of magnitude applies to uncapped framerate.
Minecraft also notoriously performs terrible. Given what Minecraft is sure that might work for Minecraft. It wouldn't work for an AAA game.
Mainstream gaming will never catch on the Web. But Mozilla is working on WebVR to create an open and distributed platform for VR (https://mozvr.com). You'll be able to publish VR content in seconds and traverse from world to world. WebGL2 is exciting for that space.
In practice, service workers seem to mostly be drive-by installs of forms of hostile code. Look at "about:serviceworkers" in Firefox to see what's running. Did you ask for any of those? I have, excluding sites where I have a login:
* https://www.youtube.com, https://plus.google.com I've never signed into Youtube, or Google, on this machine, but have watched YouTube videos.
* https://www.bajajfinserv.in - A financial service in India. I was checking out something from Wikipedia, and this drive-by installed.
* https://www.theguardian.com - I've read their site, but do not have a login.
* https://weather.com - checked weather, don't have a login.
* https://v6p9d9t4.ssl.hwcdn.net - No idea what this is. Going there returns XML with "<Message>Access denied.</Message><Details>Anonymous users does not have storage.objects.list access to bucket itchio.</Details>".
* https://fee.org - "Foundation for Economic Education", a right-wing think tank. Does a drive-by install for any home page access.