In near future browsers will ship with something that is better than transpilation (to js, that is).
W3C community group is working on an open standard called Web Assembly which is a new portable, size- and load-time-efficient format suitable for compilation to the web.
It is a better option than compilation to javascript because:
The wasm AST is designed to be encoded in a size- and load-time-efficient binary format. WebAssembly aims to execute at native speed by taking advantage of common hardware capabilities available on a wide range of platforms.
While the spec is not yet set in stone, multiple browsers have introduced preliminary WebAssembly support already.