It's not only non-phoned accounts, I have a 20+ year old account from the Beta that just got its storage limit reduced. As well as the 17 year old account I made for open source projects when I was at Linden. Both accounts have working phone numbers associated with them.

I recently moved to Proton Mail. It's not perfect, and for all I know they're sharing my info with baby-seal-clubbing pedophiles, but it sorta feels good to have escaped the thousand-year-data-reich.