Sure, but Rover is presumably benefiting from a much better economy of scale and bargaining position (since it's buying for however many thousands or millions of users it has), whereas you are unlikely to be able to do the same as an individual.
Yes but at that point and for the price it's a convenience/time thing. I probably spend 250 or 300 a month on dog sitting through Rover. The time it would take for me to find a way to self insur is worth considerably more to me than 300.