How come evolution never developed the wheel?

Wiki seems to give the wrong impression about roos' locomotion. They rest on their hind legs and tails but I have not seen evidence of them moving just with those.
When they want to move slowly such as when feeding they will place their front feet on the ground and supporting themselves on front feet and tails swing their back legs forward, move a bit forward on the back legs then repeat. That I guess would be pentapedalism.