I think that the opportunity costs are just too high.
Since the reliability of these machines seem very low, even having 2 machines doesn't guarantee that you're always able to serve ice cream.
And if you're able to serve all your customers with one machine, in times when both are functioning, the second machine doesn't really enable more sales. But you do have to power it, have a dedicated space for it, have someone clean it daily, and pay for the maintenance contract.
It's probably more beneficial to dedicate the space for an extra ice-cream machine to storage, frying station or something else that is more useful.
Another point is that I don't think not being able to sell ice cream reduces sales that much. Because by the time you find out the machine is broken, you're already in the store or drive through anyway
They're not that unreliable, but it seems like they're more unreliable than they actually are because they sometimes lie to customers -- it's easier to say it's broken than explain what is actually happening.
You see, demand for ice cream is very weather driven and that means nearly everyone wants ice cream at the same time. But each machine has a throughput limit. So, a lot of the time when they say the machine is broken, it's really just that the demand has exceeded the machine's capacity, and it takes awhile for the machine to freeze the ice cream mixture when it is refilled. If you had a second machine, that's when you switch to the second machine and by the time that one's capacity is reached, then the other machine will be ready to go again.
The machines also do what modern refrigerators do and they run a defrost/heating cycle to prevent ice from building up on the cooling equipment inside. If a defrost cycle happens at the same time as a freeze cycle, it extends the downtime because it then takes longer to freeze the ice cream mixture.
> to storage, frying station or something else that is more useful.
Storage and frying capacity is not at problem at most McDonald's. Two things they do really well is frying and just-in-time delivery.
> by the time you find out the machine is broken, you're already in the store or drive through anyway
A lot of people come with a car full of kids just for ice cream, they go to your competitor when you don't have it. If they didn't want the expense of an extra ice cream machine, they could keep ice cream sandwiches in the freezer and offer those as a substitute when the ice cream machine is locked out in a freeze or defrost cycle.
Most of the sales at a McDonalds are via the drive-thru. Inside sales have dropped so low that many stores don't even staff the front counter, you have to enter your own order at a kiosk in the lobby or use their mobile app.
I think your conjecture was correct 20 years ago but not at store with the latest remodels. Counter sales and inside dining are an afterthought.
The ice cream machines (all restaurant equipment, really) is very expensive and you generally don't buy more than you will actually use.
An ice cream machine costs less than $3,000. The whole McDonald's costs $1.5m - $2.5m. They could buy a second ice cream machine with 2-3 day's profit.
Since the reliability of these machines seem very low, even having 2 machines doesn't guarantee that you're always able to serve ice cream.
And if you're able to serve all your customers with one machine, in times when both are functioning, the second machine doesn't really enable more sales. But you do have to power it, have a dedicated space for it, have someone clean it daily, and pay for the maintenance contract.
It's probably more beneficial to dedicate the space for an extra ice-cream machine to storage, frying station or something else that is more useful.
Another point is that I don't think not being able to sell ice cream reduces sales that much. Because by the time you find out the machine is broken, you're already in the store or drive through anyway