So every McDonald's has an ice cream machine as a more sort of "break glass in case of emergency" situation. Or in this case "in case of DQ". But if there is no DQ in the area, why operate the machine? Just have it be "broken". It's not like people have an option they didn't have before.
Why operate the grill or fryer? To sell food and make money. Instead of selling someone a meal for $7 McDonalds can sell them a meal + a mcflurry for $10. Why wouldn't they want to do this?
It doesn't make any sense that a bunch of franchise owners are all in together on some kind of ice cream conspiracy. Surely the truth is less interesting, it's most likely just a boring cost/benefit analysis. There seems to be some flaw with the machines they use that make them particularly prone to breaking down and difficult to maintain. So some stores that don't sell a lot of ice cream anyway decide it's not worth the cost of keeping them running, while other stores that sell more do keep them running.
And surely it's no coincidence that the markets where people buy more ice cream are also where Dairy Queen stores are more likely to open up.
you're assuming the consumer has a marginal $3 to spend and wouldnt instead spend $7 on a (burger + mcflurry) vs (Burger, fries, soft drink). I would guess that the latter has a much higher margin. So for the same $7 spend you can make more profit if your icecream machine is down.
But, if DQ can do the deal for $7 then foot traffic may move to DQ, meaning McD's loses _both_ profitable options. So, the game is to dissuade the market from the preferred package (burger + icecream) towards the more profitable package (burger , fries, softdrink) .
I'd also add that they probably know that the marginal cost of driving to 2 locations means they're just gonna get what they can at 1 stop. That is few people would buy the burger at mcdonald's and then drive to DQ for the mcBlizzard.
Kinda feels like playing roller coaster tycoon all over again.
And I agree with you, it's likely got a way more pedestrian and human answer. The machines require some amount of maintenance or repair that is simply annoying. And eventually, people prefer to not be annoyed. So maybe one day, you just let the ice cream machine be broken instead of doing the annoying thing. Even if the store sells ice cream like gangbusters. The guy slinging cones for minimum wage isn't seeing a single cent difference if he sells 1 or 1000.