Reaching a gold status for life is worth more than the miles alone. You pretty much always fly first class for free, and you get 2-5x miles on every flight. Also, all tickets effectively become like full fare tickets. Want to extend a trip by a few days? Just call the number and it will be taken care of.
He now has 4M miles, by taking advantage of the status.
American Airlines gold status (the lowest frequent flyer status level) is not actually that generous. It's basically priority boarding, a little bit of priority on the upgrade queue (if you want to pay for the upgrade with upgrade vouchers or cash), and that's about it. Lounge access doesn't even come until platinum, one level above gold, and then only on international flights.
I'm sure he makes lots of good things happen by paying for them with his copious of miles, but it's not from the gold status :)
Eh most elite status programs have been severely nerfed. AA doesn't do unlimited upgrades (like Continental and now United) except at the highest tier. (Upgrades are only mostly domestic AFAIK.) Gold level bonuses on miles are like 50%, and it depends which fare class. Lounge access on United only happens if you're Gold and going International.
They reduce or eliminate the fees for certain things like award booking, and same-day flight changes. Changing tickets still also depends on the fare class of the ticket. If you buy a low-end restricted fare, you'll pay heavily to change it. They aren't magically turning your tickets into full fares.
Depending on where you work, a great benefit of status is that you can expense economy tickets (Y/B fare) but have a near 100% chance of upgrading.
He now has 4M miles, by taking advantage of the status.