I flew over 100K last year for the first time, all leisure travel. As pointed out above, getting the vacation time is the big problem. I solve that by working at a university that offers significant vacation, then working less than full time.

If you watch carefully for the sale and mistake fares and are willing to commit quickly (because they can end sometimes after only a few hours), you can sometimes get high status on not so much money. I have DL Plat and UA Premier and I'm guessing I spent less than $4000 for air fares last year. This year I won't fly that much, but I'll still make DL Plat, and for less money because of the DMQM offer.

There are people who skillfully manage bumps and use the resulting vouchers to fly for free, or close to it. I haven't progressed that far, but that will be my aim once I retire.