U.S. Symphony Orchestras

Here's a link to a Wikipedia list of US symphony orchestras. What immediately struck me was how large a list it is. For instance, from my adobe in southeast Michigan I have access to four orchestras, including a major one, the Detroit SO. This may sound heretical, but are there too many symphonies? The poor economic health of many of the orchestras would support the over abundance argument. It's possible that a severe contraction in the number of orchestra could occur.

There was a "Gramaphone" article a few years back about the top twenty orchestras in the world. US orchestras showed very strong with seven institutions named. Anybody have any ideas about how to keep the best of these orchestras solvent and still performing?