Ah, also relevant, a FFF one year after Wube started working on improved modding capabilities :
The big part of the work on the modding capabilities of Factorio was done during the days we were unsure about the its future. Working on something that could be used to extend the game that we were not sure anyone would play at all was looking useless. Hopefully we are still here, and new mods are arising. Some of the mods are simple but useful, like the TIme buttons, that is patching the lack of time speed configuration in-game, some are just tempting to be used because of the pictures, like Mocombat, for people that found the production chains not complex enough, there are the content-based mods like Dy tech, F-Mod and more. The growing variety of mods can only exist because modders pushed us to extend the moddability regulary and it proved more than once, that the extended interface was handy to have later even in the core Factorio, not mentioning that mods are also great incubators for new ideas that could grow into the vanilla game. So after all, we rate the time invested on modabbility to be well spent.