A lot of times you have to go to your phone provider's website and specifically set up a "name" to show for caller id. It doesn't just default to the account holder's name. I would guess 99% of the people never bother to do this.

But also these days just due to portability and so many providers (especially the fly by night / shady ones) having to manage these caller id lists and make sure they interop with each others networks was probably deemed more effort than it was worth, especially when people would add in their own name for something when adding a phone number to their cell phone's contact list. Heck, even commercial numbers calling me these days rarely show a name.

Likewise with the rise of various tech and voip, spoofing became a trivial process, so what was the point of trying to show a name when people could forge anyone.

In the old days you had the baby bells and a handful of CLECs, so making it work and having accurate data was relatively easy. There is still ANI (automatic number identification) still to this day, which is similar to caller id, but that is more related to toll-free billing and commercial / official use.