I made a move in Chicago back when American decided to put spend requirements for Executive Platinum and then also prioritize upgrades by recent spend. I leveraged a cheap January vacation to London on VS PE and a couple of business trips to challenge to Platinum on Delta, then picked up the Amex and spent on it to waive the MQD.

I could do it because I had near total flexibility on my work travel schedule at that point in my career. So for example I'd fly DL ORD-SLC-LAX or MDW-MSP-LAX to start a trip on a Monday afternoon or Tuesday morning, then get a nonstop evening DL LAX-AUS Wednesday night. After the second set of meetings, fly AA AUS-ORD or WN AUS-MDW to come home. And two of my frequent destinations were LGA and ATL, where DL was self-explanatory.

Even with that, my work travel mix until I moved away mid-2019 was just 60% DL, with 20% WN, 20% AA. And this was pre-COVID.
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