I could see maintenance costs increases being not insignificant over time. Parts/appliances had gone up notably, as has materials and the cost of people to do the work. There's also some issues with receivables which may end up needing to be written off, and deliberate damage over time. Generally, these do need to be accounted for on a going-forward basis.

That said, none of these should have increased nearly so much as the cost of property and overall rents. They should account for a reasonable increase over time, instead what we see is increased to cover the cost of the mortgage on additional rental properties etc