[modeless]

For that to happen, OS vendors would have actually had to care about sandboxing and security, to enable local execution of completely untrusted code without any gatekeeper. It's their complete security failure, still continuing today, that forces everyone to the web.

The other, slightly less important thing is petty rejection of cross-platform APIs (e.g. Apple's refusal to allow Vulkan support in macOS). It's fine to additionally have platform-specific APIs, but there should be a least common denominator cross-platform standard. But middleware can smooth over this problem, while the security problem is something only OS vendors could fix.

Unfortunately, the position of gatekeeper turned out to be so profitable that vendors don't actually want to improve their security to the point where it's unnecessary. And they're also incentivized to prevent the web from improving to the point where it would threaten their gatekeeper status.