If I buy and download a game from Steam, I trust it to not contain malware. That's why I allow that game to run with very little protection.
If I visit a random website, I have to be prepared for the worst. And if I visit any website that finances itself with ads, I can assume that they will behave like offensive attackers trying whatever they can to collect more information about me in ways that I do not want.
As such, WebGL needs a very strong sandbox around it, to prevent rogue websites from causing harm. For desktop games, that trust issue does not arise, because they have a different business model.
That's why in my opinion, desktop OpenGL will always remain faster than WebGL.
WebGL does have a strong sandbox, just like HTML/CSS/ES do. But desktop OpenGL has a strong sandbox too (by API design, process control, device memory paging protection, etc.), so I’m not sure why you’re thinking the threat models are any different, it’s just as bad if a game secretly hacks your computer as if a web site does. Desktop OpenGL development is dying anyway, so it doesn’t really matter how fast it is compared to WebGL in the future, but I don’t believe it is faster than WebGL due to any sandbox differences. Whatever speed differences exist are there due to features and design and speed of the host language.
Maybe yes, but then that's only market share lost to DirectX. I don't see the triple-A video game market shrinking anytime soon.
As for the Sandbox, Microsoft recently disabled GPU virtualization because, apparently, sandboxing a GPU is really difficult. For video games, that sandbox is not used in practice. You can access pretty much all the GPU memory that you want.
As for the different threat model, a video game tends to have a clear distributor. A website is more anonymous and, hence, inherently less trustworthy.
If I buy and download a game from Steam, I trust it to not contain malware. That's why I allow that game to run with very little protection.
If I visit a random website, I have to be prepared for the worst. And if I visit any website that finances itself with ads, I can assume that they will behave like offensive attackers trying whatever they can to collect more information about me in ways that I do not want.
As such, WebGL needs a very strong sandbox around it, to prevent rogue websites from causing harm. For desktop games, that trust issue does not arise, because they have a different business model.
That's why in my opinion, desktop OpenGL will always remain faster than WebGL.