In the 20th century, new industries tended to create a lot of demand for capital. It took a lot of cash to build assembly lines and movie studios, of course. But beyond that, thousands of people all over the country would go to their local banks to finance the construction of movie theaters, auto dealerships, and so forth.
This meant that people with capital to lend could almost always find people eager to borrow it to finance new business ventures. This, in turn, made the job of America's central bank, the Federal Reserve, relatively easy. Anytime the Fed wanted to boost growth, it could cut interest rates and get a burst of entrepreneurs starting new businesses.
But the Pokémon Go economy is different. Nintendo and its partners obviously needed to invest some cash in hiring programmers and designers to build the game. But the sums involved here are tiny compared with the cost of building a new car assembly line. AndPokémon Go seems unlikely to produce very many opportunities for complementary local businesses. People play on their smartphones, so there's no need for Pokémon cyber cafes. Smartphones are too cheap for smartphone repair shops to be a good business.
And this seems to have severed the traditional link between capital accumulation and economic growth. Since 2008, the US economy has been awash in cheap capital. In a few places, especially Silicon Valley, that has created bubble-like conditions where every crazy ideas seems to get funding.
Yet the total sums being invested in these areas are a fraction of the overall capital people have available to invest. And in the rest of the country, people are struggling to find any productive investment ideas. So interest rates keep falling as people increasingly despair of finding ways to get high returns from their savings.
Ultimately, this situation hurts everyone, because it shows up as a shortfall of overall demand. Slow growth outside of big cities means that customers have less money to spend on games like Pokémon Go.