True, but there are so many ways that I can get gold.
1. Resource trades
2. Huts (I turned these off a while ago so these don't count)
3. Begging
4. Map trades (in a standard map, it's not uncommon for me to get up to 1,000 gold from getting paper first; on huge maps with 18 civs, I aim for 5,000 gold)
5. Tech trades (sell cheap techs for gold)
6. Great Merchants
7. Build wealth
8. When making peace, AI's give you gold if you have defeated them
9. Capturing barbarian and AI cities
10. Settled Great Artists, Merchants, and Priests
11. Shrines/Headquarters
This usually means that the only time I am in 0% research for an extended time is early in the game after researching writing and later in the game if I need gold to upgrade for an army. Thus I like to have libraries and universities out (and even laboratories sometimes) before banks.

However, this might be in part because of my style of play - yours might be different.