Upvote:1
You can play this game, but it's more complicated than that, and you have to decide whether it's worth the bother for the somewhat moderate benefits of the program.
Delta bases qualification not only on miles flown but also on dollars spent. For example currently you need to spent $15000/year with them to attain Diamond status. That's likely to go up after the pandemic.
So not only would you have to throttle your flying but also your spending accordingly.
At the moment, I believe you can roll over ALL miles from this year into next, regardless of which status you will reach (Covid benefit). So the most efficient way would be to fly as much as possible this year. Unless, of course, that pushes you under the spend target for next year.