The biggest danger to MLS, is loss of confidence by present owners and potential new investors in the product. As long as everyone involved, retains confidence, that things will continue to get better and values of clubs will continue to climb, then all will be well. If the majority of the clubs continue to lose money and any potential TV revenue looks like it might disappear because of poor television numbers, then there is always the possibility that confidence could wane.

No endeavour can succeed in the long run, if it continues to rely on new investors to keep the books balanced. Eventually, either the endeavour runs out of new investors or lack of confidence it long range profitability, causes potential investors to abandon the idea of getting involved.

As "argos1873" mentioned, NASL eventually collapsed because of over reaching with rapid expansion and mounting debts. MLS would be wise to learn from this example and be more cautious and take a slower approach to future growth. Failure to do so could result in a dot com type crash.

The warnings are on the horizon but hopefully MLS will take a more prudent approach in their business model and avoid a collapse of the league. But as we have seen numerous times in the past, no organization is too big to fail.