Agreed that Dart was an effort to do exactly this.
To be a bit pedantic... "relegated to transpiling to JS" makes it sound like that was something they had to do later, but in fact that was up front part of the transition plan. The idea was, write your code in Dart and it would work natively in browsers that (eventually) support it but would still work in everything else via JS transpilation. You're right that it was relegated to only working that way once it was rejected.
The problem was (if the Wikipedia article is to be believed) that developers took offense to one company unilaterally deciding on the future scripting language of the web. A little ironic given that's how JS evolved in the first place, but fair enough. Later, WASM was created instead, with the idea that no particular language had to be chosen (and frozen) as the JS replacement. Dart compilation to WASM followed.
To be a bit pedantic... "relegated to transpiling to JS" makes it sound like that was something they had to do later, but in fact that was up front part of the transition plan. The idea was, write your code in Dart and it would work natively in browsers that (eventually) support it but would still work in everything else via JS transpilation. You're right that it was relegated to only working that way once it was rejected.
The problem was (if the Wikipedia article is to be believed) that developers took offense to one company unilaterally deciding on the future scripting language of the web. A little ironic given that's how JS evolved in the first place, but fair enough. Later, WASM was created instead, with the idea that no particular language had to be chosen (and frozen) as the JS replacement. Dart compilation to WASM followed.