I don't think it's so much that he's an insider as much as it is a couple of things.

One, he's older. Like in his later 40s. He's also living with a much better quality of life. It's also hard to be intense when you have a somewhat luxurious life. Even take Nas and Life is Good. It was a great album but it doesn't have the intensity that he had on Illmatic or I Am.

Also, apparently, people are the most prolific in their 40's but the wildness of the imagination gets tamed before then. That could play into his lack of lyrical imagination.

Two, he's in a better space mentally. Like you said he's into health and wellness now. While he's always been somewhat positive, he's even more so now and it's simply hard in hip hop to come off hard and sharp-edged yet compassionate. I don't know anyone who's really been able to pull that off because we take empathy to be corny for the most part unless it's done exceptionally well.

As far as him not having anything more to say, there's truth in that. If only because he's older and touched a wide range of topics over his career.

I'm not an artist, but I used to keep a blog, and it is REALLY difficult to mine ideas and topics and do justice to them after a while. I literally stopped after a few years because I simply couldn't draw anything meaningful from myself. The well just ran dry.

If Common simply gave more time in between projects to let ideas form on the own schedule that might help. There aren't really superproducers anymore but I wonder if he decided to work with someone who really knew how to draw fresh material out of him if that would spark another great album out of him.