[jpdaigle]

Water heaters and furnaces can be leased instead of purchased, for a few dollars a month. (But it's more expensive in the long run.)

What's different about a furnace vs a fridge or dishwasher?

[lotsofpulp]

Furnace longevity depends on how good the owner is at maintaining clean filters, and water heaters depend on water quality. I'd find it difficult for either of those to be offered as-a-service at a reasonable price considering the aforementioned volatility versus just selling them since they're not that expensive in the first place.

[alex7o]

Yes but in that case it would be in the interest of the leaser to make the product be as easily maintainable as possible.