gmail and yahoo have not shut down, so i've had no reason to stop receiving mail from those accounts. if i so desire, i can keep renewing a .com domain almost indefinitely for a pittance, and run my own mail for the domain. on the other hand, every 1-2 years when my mobile phone and/or internet connection contract runs out, i reconsider my phone plans. free phone number portability is relatively new thing compared to how old gmail,yahoo mail and hotmail(or running your own mailserver) are.