It doesn't work that way. Technology almost always can be used for more than one purpose. WebAssembly will grow the web a lot. Sure, it might replace some exist

It doesn't work that way. Technology almost always can be used for more than one purpose. WebAssembly will grow the web a lot. Sure, it might replace some existing parts, but that's not because WebAssembly is "evil" or "closed", but because some publishers/sites/folks want to go into that direction. They are probably already doing a lot of "closed" stuff. DRM? IP restriction? Continuous connection checking or the site stops working? Idiotic session timer? Restricting registration to certain users for no real legal reason at all? Obfuscated HTTP API? The list goes on. Worrying about dumb technology is irrelevant. (If you want to worry about tech, worry about AI, that has the potential to really cause problems.)