[spyhi]

If you think about it, it kind of makes sense. OP is in a situation where he haas much more money than time, however due to his position in the world, he can see many opportunities--generally this is true for professional investors, too. For a normal person, pursuing one means there is an opportunity cost, but for an investor it makes sense to buy a slice of the action in an opportunity they believe in. Being a proper investor (mentoring, introductions) also takes time, so that's another disincentive from OP's perspective to being a founder vs a funder.

Also, investors have things thing about inventing the future by funding it. Generally, individually or as a group, they'll decide something is going to be the next big thing and start cultivating deals in that area. One you can see happening in real time is space: Randomly in the last couple of years, investors have put together huge funds around space ventures, even though serious commercialization still seems to be a ways off. Even OP referenced it in his blog post.

As for why a founder vs a compensated product owner? Because a founder presumably has spent a lot of time thinking about the problem and is intrinsically motivated to solve it--so much so that they've done all the legwork to assemble a team and gather enough data to be investment-worthy. If as an investor you're wrong about the opportunity in this space, it's a whole lot of risk and cost and time you don't have to take on yourself. By advertising a pot of money, instead of searching for the right person, the hope is that the right person and team will eventually come to your door.