Aside from those two reporters quoting an "anonymous source" (which is clearly Trace Armstrong), we've got nothing else. No word from anyone close to the Eagles, no details about when, where and how the meeting took place, etc. Just the bare minimum that an ambitious agent would want released for public consumption.
How do you define "well"? Flirting with Chip Kelly and Saban (neither of whom are going anywhere, btw)? Few college head coaches make the jump to the NFL, and even fewer find any sort of success there.
It all depends on what he considers to be the top rung of his personal ladder. He could make more money in the NFL, but he'd have less control and a lot less job security. Hard to compare them.
It's still a destination job today. Name me a coach that voluntarily left ND for a better gig. You can't, which would make Kelly the first. And yes, NFL coaching salaries have grown, but the salaries for top CFB coaches have grown apace. It's not the obvious next step you make it out to be.