He has a point though. Gold mines are the only really viable way of building an economy early game (and they still make up the bulk of the economy late game too!).
Sure gold is useful in real life too but somehow real life historical kingdoms managed to get a lot done and accumulate a lot of wealth without having huge gold deposits!
In fact pretty much every big and wealthy historical city was known as wealthy because of trade, production, etc, rather than because they were all built on gold mines!
Trade, production, gold? Nonsense. All the great Kingdoms of Elemental built up their wealth by slaughtering giant spiders, which seem to breed like rabbits in any forest just outside civilized territory. It's the only way to go.
Seriously though, sarcasm off: got to tune down the monster economy, and give those who research civilization some buildings that generate reasonable gold on their own, not more percent boosts that depend on gold mines. Right now your choices are 1.) slaughter monsters, or 2.) research some adventure, and with a little luck you're swimming in gold mines. Whatever happened to the civilization techs, isn't that supposed to be where the economic stuff is? It's honestly not my thing, but I know some people love the "building" (that is city/economy development) aspect of the game, and it cannot stand on its own at the moment. I personally love adventure research, for the questing and exploring aspects, but it feels wrong that it's also the best (and arguably only) way to build up an economy, it's so good it feels like cheating.
Not to say civilization is useless, it still has its place for prestige and percent boosts to the base resources, but it's strictly subordinate to first getting enough adventure to bury yourself in raw resources. Civ needs more buildings that generate resources on their own, without depending so much on adventure or simple luck with natural resources. Simply changing "market" from +25% gildar to +4 gildar (equivalent to that +4 material mill) would be a big step in the right direction - not a complete fix on its own, just an example of the kind of change needed to make civilization viable, and help builder-type players be less dependent on luck/adventure/spider slaughtering.