The fact that the UFC never signed him says a lot.
Meh.
They clearly didn't sign him for three major reasons:
1. Too much shit flying back and forth between he and Dana.
2. He was getting offers elsewhere that they didn't want to compete with because his style isn't one that they feel draws viewers.
3. They were actually a little worried he would win fights (and maybe even make a contender/title run) against guys who were a draw.
People act like Askren was a no name fighter who wasn't on the UFC radar. Reality is, if they were confident that he'd get eaten in the UFC, they'd have signed him years ago to put him in there against the sharks of the division to be exposed and to shut him up.
For the opposite scenario, see Kimbo Slice:
1. Respectful to Dana and Co.
2. Brought a really big viewership with him.
3. Probably wasn't going to go far, but if he did that would just be a bonus because he was super marketable.
Doesn't mean Kimbo was a better fighter than Askren, just because he fought in the UFC.