I find it interesting that your example for "benefit of hindsight" is TypeScript. TypeScript is a superset of JavaScript, so it's literally "just add good stuff to the bad and live with it". Am I misunderstanding something?
Traditional JS with new features added, or traditional Node with new features added is the opposite case, where the old standard is being extended, unlike the TS or C+asm case, where the new standard has a mechanism for calling back to the old if necessary. (Deno could still be what I'm talking about even if they added a Node-emulation-library to allow it to call modules written for Node, but I have no idea whether such a thing is planned.)
I love TS as much as the next person but I don't think it's particularly good example to use here.