With the entire economy valued at $23 million I'm not sure if there's enough room for a second stock exchange.
The entire economy is not valued at $23 million. The value of all the bitcoins in circulation in USD is $23 million. There is a HUGE difference.
There are many things that go into valuing an economy, potential and reach being a major one. You also need to calculate users, the value of all Bitcoin business's, and many other things that go into it.
The bitcoin industry is hands down worth at least $500 million- $1 Billion.