I'm not a lawyer, but my understanding is that you can't have something that looks like a sale and call it a rental. If Lexmark wants to rent printer cartridges, they'd have to spell out a term for the rental (can't be indefinite), collect rents, make reasonable attempts to reclaim their property from deadbeats, etc.

They'd also have to carry all those cartridges on their books as inventory, and therefore conduct audits, depreciate the value, etc.

The law does not generally look kindly on "hacking" - if it looks like a duck and quacks like a duck, you can't call it a swan just because that would be more convenient for you.