The number of ideas need never go down in principle. Human creativity is inexhaustible. But the yield rate may start to go down (i.e. success percentage), with the numbe of viable markets going down. Analogy: you can keep drilling exploratory oil wells all over the planet, but once 'Peak Oil' hits, actual 'finds' may slow down. Or to put it another way, the total number of ideas, including stupid ones, will not go down, but the proportion of "stupid" will.

Japan is ahead of the rest of the world in thinking this way already. There is a satirical movement there called Chindogu, "unuseless" inventions -- apparently functional, but deeply stupid:

http://en.wikipedia.org/wiki/Chi...

Since humans don't like low yield rates, they may move on and invest less in coming up with ideas, so the total number of ideas may also go down. Why continue drilling if your chances of striking oil are going down every day?

I believe "Peak Market" will happen, just like peak oil. Unlike knowledge, for which a case can be made that it is infinite, it seems mathematically impossible that there can be an infinite number of markets representing infinite wealth. At least not while we are stuck on Planet Earth. If we invent The One Great Invention: hyperspatial/warp drive travel, we may find a frontier of endless growth.

But on earth, the 'market' represents the aggregate of all the things we demand as a species, along with the prices we are willing to pay for them, and the products/services in the supply chain that makes them. Greedy though we are, we are not infinitely greedy, simply because we must also be the ones that make everything. And at some point, the massive complexity of the world we are building will be too much. Computers may already be too complex for the mainstream, hence the iPad.

So the number of grounded startup ideas may start to go down after hitting a peak. We may not like the costs of growth, and may start to prefer simplicity. As Edward Abbey said, "growth for the sake of growth is the ideology of the cancer cell." Entrepreneurship is about nothing if not growth. And we may come to view it as unacceptably costly, irresponsible and even immoral in social terms, the way we came to view slavery.

In some ways, this movement is already starting, as with the Slow Money movement (which currently focuses primarily on sustainable local food security, a movement called Slow Food). Here is a quote from their website:

In order to enhance food security, food safety and food access; improve nutrition and health; promote cultural, ecological and economic diversity; and accelerate the transition from an economy based on extraction and consumption to an economy based on preservation and restoration, we do hereby affirm the following Principles:

(emphasis mine). Slow money site: http://www.slowmoney.org/

This may seem like wooly-headed left-liberal utopian dreaming, but the movement was actually started by Woody Tasch, an investor who has pioneered social investing.

I don't completely agree with the slow money movement, but the point is, it is one of the first critical reactions to too many decades of thoughtless "growth for growth's sake" varieties of cancerous entrepreneurship based on the idea of free market capitalists making a pile of money, and running away before the social costs became obvious to others, at which point everybody had to pay for it.

That kind of irresponsible capitalism may slowly die down, and with it, unbridled pursuit of entrepreneurial ideas and wanton "drilling for markets."