I think you must be off by a couple orders of magnitude. Wikipedia's list of programming languages contains a little over one thousand entries. Many of those languages are only interpreted, with zero compilers ever written, and only a small number of popular languages have ever had more than one compiler written. It seems very likely that thousands of compilers have been written in total, and tens of thousands are plausible, but if we consider hundreds of thousands, it's hard to imagine where so many compilers could be living, or why they would have been created.

Trivial with an LLM yes, but in reality nobody will bother with a full rewrite in another language just for fun if the original program works, but is a bit annoying to run.

This way it's pretty close to zero effort.