Let's look at an E-9 Master Chief, the highest enlisted rank. Their basic pay is $9267 a month[0]. If they're in for 30 years, and get the High-36 retirement plan[1], then they get 75% of that — $6950/mo — afterward. That's certainly not chump change.
However, the kind of person with the drive, leadership skills, political savvy, and work ethic to become a Master Chief would rise to least a director or VP, or a senior VP, at a civilian company. So yes, their military retirement's quite good, but at a substantial opportunity cost.
To be super clear, my main argument is that the military should earn more, especially for the sheer amount of work they put in. They earn it.
I don't deny that servicemembers earn their pay. There is a premium to accepting the upheaval of a cross-country move every 3 years. But to assert that the average E-9 is equivalent to a director or VP position is incorrect. People of that rank are told in TAP to accept positions of perceived lower authority. Those who are successful in going from E-8 or E-9 to Director or VP roles are extraordinarily rare.