We understand the concern here at Wit. It's free because we no longer need to generate revenue. Wit developers spend time validating data that is critical to improve the models for the Wit community.
When we joined Facebook in Jan 2015, we updated our Terms of service to mention that you can retrieve your training data if Wit closes at some point. FYI, the training data (expressions, intents, entities) is the critical component. The plan is to continue supporting and growing the product. The release of Bot Engine Beta a few months ago is a proof.
The fact that you're saying "it's free because we no longer need to generate revenue" is exactly the problem. It means you didn't even think this through. If you had, your answer would be different.
It's just like Twitter saying "We don't need to generate revenue directly from our API and that's why we're opening it all up because what's good for the community is what's good for us!", except that this isn't 2006 and everyone knows better.
Our vision is to make it easy for developers to make apps or devices that can leverage AI/NLP/Speech. As you probably know, the key is the amount of data you can collect. The more data, the better your models will be, the better you API is. When you are a startup, you need at some point to generate revenue to continue to grow/hire even if you objective is to gather more data
