The benefit is that ability to compile that old code, even if it takes some flags or marking it unsafe or whatever.

There is a lot of old code that will never be rewritten but is still valuable, and I believe we will waste a lot of time just language-shifting entire ecosystems as new languages come and go.

Look at python 2 to 3. There are still packages out there on python 2 that haven’t been migrated. And thats mostly the same language!

(Note that my view is colored somewhat because I am a scientific programmer)