Bounties are a great tool. They’re particularly appropriate for situations like nostr which are primarily new web/mobile client interfaces to open datastores on the internet. Tons of innovation can be unlocked with appropriate bounties to instigate open source software projects that can provide a net-good for humanity, but end up corrupted in various ways when they’re owned by a centralized party.
Venture capital is a different tool than bounties. It’s useful when you need to marshall a lot of resources (both financial and human) to accomplish something really big in a very short amount of time. For extreme examples think about launching rockets and telecom equipment or designing new pharmacological theraputics. I hope some day we can do this fully open source and with a bounties-like approach, but I don’t want to slow down progress just to wait for that day.
It’s not always clear which of these tools or others should be used at any given time. But if something can be accomplished with a bounty it probably should be, but I don’t believe everything needed to be built can be accomplished with bounties so it’s good to explore other funding/risk-capital sources or even to design new models for financing this risk.