It's not a cost of ownership figure. By definition, if you're paying Tesla or Wells-Fargo $1,200 a month for your car, your cost of ownership is at least $1,200 a month.
Rent one from me for $1500 a month. That will save you the $1200 you otherwise would pay to Tesla, so your total cost of ownership is only $300 per month.
In other words: your logic does not make sense to me.