In a nutshell, this video explains that McDonald's franchisees are required to sign a contract that restricts them to use a particular model of Taylor ice cream machine that is intentionally prone to malfunctions so their service / repair staff can fleece the local franchisees for up to $315 per 15-minutes labor charges.

The REAL Reason McDonalds Ice Cream Machines Are Always Broken

I was thinking that it seems to parallel the problems associated with the John Deere repair policies.  You can make a lot of money from repairs if the customer has no other options at his disposal.