Ask HN: online Work a winner takes it all market? Elance vs. odesk

I am a frequent user of marketplaces like Elance and odesk where I offer my services as a .NET developer. I thought a lot about the nature of hat market and how many platforms  we will have as the markets matures over the next 5 years. The main questions I would like to answer is if that market is a winner takes it all market and what are its characteristics. 

For example Facebook is a winner in my opinion. It might get replaced but I do no see multiple social networks co-exist due to strong network effects and switching costs.

For online work and the current platforms available it is not so clear for me. I do not see a big advantage for a developer like me if I signed up with a platform having 15000 or 100000 projects. For a contractor it's kinda the same. A platform with 15000 or 100000 developers does not concern me. I do not see a strong network effect. Switching costs aren't so high as well. 

I would expect to have maybe 4-5 big players worldwide. I don't see multiple platforms like over 50+ neither. It would be too hard to maintain for human in my point of view.

However, I have observed something interesting in the data Elance and odesk disclose for the market in USA and Canada. The past two years odesk seems to show a monthly growth rate which is way higher than the growth of Elance if you look at number of projects and number of service providers. I am not sure if odesk managed to steal a market share from Elance since both compani are growing. Anyway, if I look at the exponential growth (oconomy at odesk) it feels like that the reason for that growth can't be only operational excellence which brings me back to market effects/ dynamic.

If you have any more insights I would love to discuss with you because I am personally interested in topic. I think in the future online work will play a big role how humans work. 

To sum up, will there be one player one In that market which takes it all?

Is it just a money game? By money game I mean the player with the most funds will win? 

A the end I want to apologize for my English. I am not a native speaker which stopped me from posting earlier, but I still hope m points are clear and we will have a good discussion. I am happy to answer any questions.