Not a fair comparison, since, I was talking about a backward compatibility, but you are talking about older language, supporting programs, developed for the newer syntax, unless, you were joking.

Sorry, I was joking and made a poor joke. All I was trying to indicate with my bad joke is that in:

The abundance of Python 2 programs will not run under Perl 3

you made a typo: Perl 3 Python 3.

And yes, re Python 3 breaking compatibility with Python 2, I strongly agree with you.