While perl is correctly lazy in it's evaluation of a ranage, it get very industrious when you wish to pass it to grep, map and friends.

Completely backwards. Ranges aren't lazy. There's nothing special about how grep, map and friends interact with ranges.

does anyone know why perl's own functions have never been changed to the appropriately slothful?

The parser could replace grep BLOCK RANGE with something equivalent that doesn't involve a range. This is what it does for for (RANGE).

I'm guessing it's simply a question that noone has taken the time to do it.