@OlivePit Maybe one thing your not taking into consideration is that the Devs don't want crop yields to be totally predictable in the first place.
They know that in a testing phase, they are probably going to get more people more focused on building up the cities as fast as possible, because they aren't really going to worry about the long term effects of crop maintenance, but in the long game, fertility is going to go up and down by crop rotation, and they may even institute things like diseased crops or massive environmental damage to farming areas in the future. By not instituting the 3rd crop now, they are keeping that element of uncertainty, and then when they do introduce them, they will have worked out, internally, what other factors they may want to include with the introduction of veg.
One thing I think they do want to avoid in Fractured is making everything predictable throughout the game, and instead add some elements of chance and circumstance into the mix. Also, they coding for the 3rd resource may not have met with the devs approval by the time frame that they wanted to release the Beta, and they felt that it was not something worth delaying the Beta release for in the scheme of things.
Finally, they did not promise NO wipes during the Beta, they just have no planned wipes as of now, and that's character wipes. Nothing whatsoever was mentioned about city wipes, and yet, available city plots and their locations may very well change as the Beta evolves, so such wipes may indeed be in the cards, generally with appropriate warnings issued when possible before doing so. Even full character wipes may happen, depending on what bugs and feature-changes end up needing to be implemented. The point is, no wipe is planned at this time for testing, other than right before actual launch. Who's to say what else will happen in the meantime.