Without rollover, my choices on airline depends if the value of the benefits outweighs the costs (especially at ATL where DL seems to charge a premium).

I’ve hit the GM qualification threshold, and won’t have enough spend to get to PM this year. For an upcoming flight, DL wanted $450 while UA (silver status) asked for 15k points, so I booked the United flight. (Though maybe the benefits of PM or DM might be more incentivizing to warrant staying on DL even after hitting the MQD threshold)