Author here. I should've worded that better. The recommendation is not to stop compiling TS->JS for npm users. The whole npm ecosystem is built around the assumption that you ship JS and doing anything else would break it.
In Deno (disclaimer: I work for Deno), which supports running TS natively, packaging outside of npm has always worked by shipping the TS files directly. Transpiling them down to JS files is only something you ever had to do when publishing on npm.
So far the problem that a dependency only compiles with a certain version of tsc hasn't popped up since Deno was launched. But that may have been because Deno always ships with latest TS and Deno users don't hesitate to update as we haven't done any breaking changes so far.
In Deno (disclaimer: I work for Deno), which supports running TS natively, packaging outside of npm has always worked by shipping the TS files directly. Transpiling them down to JS files is only something you ever had to do when publishing on npm.
So far the problem that a dependency only compiles with a certain version of tsc hasn't popped up since Deno was launched. But that may have been because Deno always ships with latest TS and Deno users don't hesitate to update as we haven't done any breaking changes so far.