I wondered the same thing and just to speculate, here's my list of reasons on why phone number search is so awful:
- As far as I know, not a single cell phone carrier publishes a telephone directory (whether opt-in or opt-out). So there's no (public) data to index.
- Some landline carriers still publish telephone directories, but of course landlines are dying out. And I remember reading that 30-50% of landline subscribers choose to be unpublished or unlisted anyway. So that source of phone number data is drying up.
- Because international phone calls have become so cheap and caller ID is now easily spoofable, spam and scam calls have become huge. So no one wants their phone number to publicly accessible these days.
- In the early web years, there were legitimate phone directory websites who appeared to have collected their data from landline telephone directories and "city directories" (if anyone still remembers those things). But I guess they didn't find a good way to monetize the service, so the honest phone lookup sites died off.
FFS, 411 was amazing before the web.
Also, in about 1989 my friend and i used to have a contest between us; to call 411 and see who could keep the 411 operator on the phone the longest.
This was a fun social engineering exercise for 14 year old nerds who like the idea of being phreaks.
Our record was 45 minutes and got to know a lot about the 411 system, where call centers were located and how the 411 system worked.
This was right near the time that we ran the long distance bill up to $926 for one month of calling into a BBS in san jose and PCLink to chat....
Got grounded for a month for that one...