People frequently dismiss "idea people" with the claim, completely baseless, that "ideas are a dime a dozen". Well let's look at this claim.
We're interested in good ideas because it's easy to establish that just like there's good software and bad software, and people routinely dismiss the bad software, so there are good ideas and bad ideas. So we know there is a differential in the quality of ideas. And for anyone who bothers to glance at the subject, it's easy enough to see that there's a differential in the quality of people who have ideas.
So now that we know there's a differential both in ideas and their sources, we have to ask how big that differential is. There isn't a large difference in the bushel price of wheat from different sources but there is a big difference in the price of houses, and this has practical consequences. One consequence is that if you talk about the average price of wheat, you're talking about something meaningful, whereas if you're talking about the average price of houses (3 orders of magnitude) or the per capita income in a country like the USA (3 or 4 orders of magnitude), it really doesn't mean anything.
So what's the differential in the value of ideas? Well, we won't bother with the bad or negligible ideas at all, even though they are widespread (MAD and warfare are just two noteworthy exceedingly bad ideas). Let's stick to good ideas. First we'll establish a lower bound for marketable ideas, then we'll establish an upper bound and compare the two.
So what's the value of the most pedestrian run of the mill ideas which are productive and which people will actually pay to get? Let's consider a process engineer or site engineer as the lower bound. And let's say that a mediocre (but competent and marketable) process engineer working to improve a production line is worth $1 million dollars to a plant (an overestimate). Now, process engineers have numerous small ideas which are put immediately into effect, fully mature, and a halfway decent process engineer might improve a production line a dozen times over a given year in various minor ways. So the minimum value of a good idea can be as low as $100,000.
Now what's the maximum value of a good idea? Well, a revolutionary idea can annihilate entire industries. Not immediately of course but once it matures; the lifecycle of a revolutionary idea is very different from that of a pedestrian idea. So marketing and advertising is a trillion USD a year industry in the USA and if a single idea could wipe out this industry, it would thus have a value of a trillion dollars. This is hardly the only trillion dollar idea. Nuclear bombs have a value around negative a hundred trillion.
So comparing the highest valued ideas (trillion) to the lowest valued (100k), one finds 7 orders of magnitude in difference. If one compares the output of the most talented hackers with the least talented, there may be as much as 2 orders of magnitude difference. 2 orders of magnitude is considered a fantastic difference. For ideas, we have 7.
(Note that for a given piece of software to have more than 100x the value of some other piece of software, you have to be comparing the value of the ideas embedded in the respective softwares. At that point, you're not evaluating the skill of a programmer as a hacker but as an innovator. Maintainability and power/efficiency of the software produced should also be taken into account.)
Good ideas are not dispensable unless you define "good" in some roundabout manner to include dispensable ideas which by sheer number vastly outnumber the really valuable ones. Good ideas are priceless treasure troves. And the cost of getting these good ideas is far from cheap. You can't get good ideas by gathering a "focus group" of yokels off the street and watching their mindless reactions. Even by creating a free-form research lab you're not guaranteed any good results despite a very large investment. So far, the cheapest way to acquire good ideas is to hunt them down in the wild, to track down sources of expertise and run them down like dogs, then bag them and string them up. EricVonHippel invented a process for 3M Corp to do just that. And even if the hunt consistently results in good ideas, each one you bag will easily run you into the tens of thousands of dollars. Good ideas are NOT cheap.
People are habituated to the cheap junk ideas just lying around them, most of which they produce. Hell, they're habituated to the horribly expensive and utterly insane ideas they have no control over (e.g., nuclear war). What they don't appreciate is the magnificence of good ideas. They don't have the breadth of thought to step back and appreciate the value of a good idea in its full scope, an idea that may easily affect every single person on our planet in profound ways. This requires imagination.
Can Money Buy Good Ideas
I would instead suggest that good ideas are "hard to find". I don't know if money can buy them, even if available. Often it is shear luck. Plus, somebody good at finding/creating an idea for topic X may not be good at finding/creating an idea for topic Y. Due to experience or coincidence or luck, they may be a one-trick pony.
It is also often said that success is everybody's baby but failures are an orphan. It is often hard to pinpoint the real source of past good ideas to see if the same people or processes can be tapped for later ideas. Often one has to give up credit to get an idea through (this is described in HowToWinFriendsAndInfluencePeople).