"Native typescript execution" can mean two different things:

1. Chrome/v8 takes TS code, compiles it down to JS internally, erases types, and then runs it like normal. This isn't going to be too hard to do, but also isn't going to be very meaningful. Compiling is a one-step process in any case, and plenty of tooling exists to make it seamless.

2. Chrome/v8 actually understands TS types at runtime, and throws exceptions for mismatches. This isn't going to be possible without a major rewrite of the v8 engine and the ECMAScript spec itself.

And a big challenge for both of these is that TypeScript is iterating at too fast a pace for something like Chrome to keep up. It's best to just leave versioning and compilation for the developer to manage and give end users a consistent JavaScript experience.