it's a damn shame that the series got axed, if it did. seems like there was going to be one more arc in high school before this timeskip, but they had to immediately jump ahead to the uni stuff.
My current guess with what happened before the timeskip is that Airi feels like her conversational skills that she was using were becoming less and less useful, like she felt more like a fish out of water and regressed perhaps. It doesn't seem like she quit uni or her jobs because she was underqualified or got pushed out; it seems more like she hated how isolated she got and it sorta spiraled from there. Thinking about how in the beginning of the series, she was thrown off guard by the otaku-kun she tried chatting up, but was able to acclimate with talking to other folks like Fumi. I wonder if as the years went by through her jobs, she ran into the same sort of problem, but instead of otaku genre mismatch, it was just like a realization that she wasn't necessarily "normal", so to speak. Her social battery life is pretty low and needs recharging, so what if she thought it all to be too much later on in life? just a theory.