True, and the cellular wave has made many phone numbers one-to-one rather than one-to-household. But for long form communication, SMS is rather painful, but it would be interesting to see something like Front built on top of it.

Not disagreeing, but a number of people have many email addresses. No idea how that stacks up with people with SMS though.

i change my phone number more often than my email address, though..

Why's that? At least within the US I can easily port a number between providers. But if I want to stop using Gmail and switch to Yahoo, I'm screwed. All of my accounts use the gmail address for my login, and most have no visible mechanism for changing it.

I don't change my phone number because it's easy to keep it. I don't change my email because the address is tied to a specific provider and getting everyone to switch to using my new one may be impossible.

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.