Late game gold?

[Velikai]

It always seems like there is so little gold.
And playing Co-Op vs AI one always seems to get super passive allies who just want to turtle and never expand. The game reaching 1 hour doesn't seem that out of the question. By which point all gold nodes on the map are exhausted.

How does one generate gold at that point? Trade?

Personally I'd rather win the game before then, but can't do anything about turtling allies.

[Rinky]

Market and a ton of Traders is the obvious answer

[Subtle Butt ( >ω<)っ ♡]

Trade

[Crokite]

A combination of Market Traders (as long i have control over the trading), and farming food witch i trade for missing resources when needed.

[Seven of Nine]

There are several ways other than Markets, although Market is the "most reliable".
English Farms + Enclosures (Age 4) Tech
Rus, possibly the weakest or least reliable: plant hunting cabins near forests all over the map, get a mongol ally to supply you with sheep etc... this can net you a little.
Chinese : Tax with imperial officers.
Relics, especially the HRE.

French can overcome it with guild hall, though it will need time to build up, a very situational landmark often neglected for School of Cavalry.

Mongols: burn enemy buildings try not to trade badly for enemy buildings... I know this sounds easier than it is done but there is that. Silk Road trading is actually one of the best eco bonuses but you really need to dump your villagers for it a bit + razing. Outpost network with Yam + Traders + Silk Road, especially in team games makes the mongols a good eco side kick that won't need villagers in late game if you know what you are doing. You will always end up having traders in any team game, why not have your traders carry back a bit of everything , even stone? After a time that stone will sell nice if you need gold :>

Delhi and Abbasid I haven't played much, but they are primarily relying on trade.