like i said, i’m going off what a guy in the Verizon store said, which is one step above pulling it out of my own ass, as far as data veracity goes.
but, if i were to guess, i’d speculate that it had to do with the disposability of numbers, how often people change providers after losing a number due to not having to pay or switching off of a parent’s plan, things like that. People used to go to great lengths to hold onto old numbers. people don’t really care as much now, even when porting them between carriers is easy.