It would be an incredible feat of engineering to be able to "transpile" an existing executable to WASM - if you're familiar with dynamic linking, the ELF format

It would be an incredible feat of engineering to be able to "transpile" an existing executable to WASM - if you're familiar with dynamic linking, the ELF format itself (or Windows' PE), the common processor instruction sets, etc - you'll know that won't be a problem anytime soon. Short of an x86 VM written in JS, it just ain't gonna happen. Now, about having other languages compiled to the web, we already have that. Looking at specifically Haskell, we have GHCJS, and it (thankfully) works pretty well. You may not like the idea that there will be new web projects using technologies that you lack proficiency in, but this is no different then how the rest of the software world works. For example, Google's Go language is picking up steam - in fact, I use it at work. If I didn't take the time to learn Go, I simply wouldn't be employed to work on that project. Similarly, I know people who are enjoying an incredible competitive advantage in their market by using Haskell for their web development (both backend with GHC and front end with GHCJS). If you don't learn Haskell, you won't be hired for those jobs. I do, however, guarantee that they'll still have the source on hand.