I think that an enlisted service member who's good enough, and lucky enough, to learn and do some technical things can easily 3x their pay by working as a contractor after their initial enlistment. But their starting point is low as an E-3, E-4. They can go from making $40k to $120k, sure, especially if they're willing to work in a combat zone.
I don't know a single O-4, O-5, O-6 (and I'm talking aviators and IT/cyber officers) who has "fallen into" making 3x as a civilian. Their pay in uniform is $160-240k. Many of them seem to opt for civil service jobs as a GS-14, GS-15, which will match their previous pay at best (but be in addition to the $50-90k pension).
I hope you're right, but I'm certainly not counting on a $600k job offer when my time comes.