He says that the market was terrible because open source developer tools suffer from oversupply. I don't think that's what happened. Rather they chose to make a product for which the next best alternative (e.g. Mongo or Cassandra or MySQL or Postgresql) had almost zero cost. It doesn't matter how oversupplied the market is if someone is willing to give away a viable product for free. Perhaps "oversupply" is another way to say "someone was willing to sell at zero cost", I'm not sure.
Unless you can find a set of customers who see significant value in your product vs. the alternative zero-cost product, you're never going to make money.