++ for this very interesting post.

I guess it is all a matter of design choices. The my variables are not specially made for the purpose to release memory when they go out of scope. May be erroneously some of us may have thought/hoped/wished they were, but as you clearly showed, they are not.

Rather their design is to encapsulate them within their scope and not "pollute" the variable-namespace outside of it. And they do that very well.

As they are mostly used in loops and sub-routines, there is a good argument to be made in favour of speed above memory-consumption. You really do not want your tight running loop to get slowed down by repeated (de-)allocation of memory!

Also, I have been using Perl for many years now and never got any of the memory-issues you mention. The examples you give are correct, but --IMO-- marginal or degenerate situations. Still we should not be blind for these issues and if you have a memory hungry program, you indeed may have to program very careful so as not to exhaust your memory. Thank you for reminding the Monastery of this!