How come evolution never developed the wheel?

Two reasons1. Not all possible variants will necessarily evolve - there aren't any tripods either as far as I know.2. The wheel and axle is can't be innervated or supplied with blood because the 'cable' would twist around the axle.

There aren't any.Rolling and wheels in the natural world - Simple English Wikipedia, the free encyclopediaThe nearest I know about would be the ratchet in a grasshoppers leg Why insects are marvels of engineering - BBC News

Wheels aren't just used for locomotion. We use them in gear boxes - effectively as levers. We use them in pulleys and as rotation devices. But the owl can't do a full 360 degree rotation for a reason - a wheel-like device can't be innervated or be supplied with blood without wrapping the pipes around the axle.

Didn't you read the answers given?Firstly there are some examples in the bacteria flagella and partial ones in the grasshopper's leg. (Also ball and socket joints in mammalian hips).But there are real reasons why wheels aren't generally used.They're only really useful on roadways - evolution didn't have roads to work with. You can't climb with wheels and you can't deal easily with broken territory.Then the wheel needs an axel and a rotating wheel prevents easy inervation and blood supply in the usual way - because cords wind around the axel. A totally different mechanism would need to have evolved. Not impossible, just unecessary and unlikely because it's not a useful feature - because there are no roads.Now, what's wrong with that?I'm interested in why there are no tripods - now why do you think that is?

Apart from the parrot conjecture, there are no known species where three legs are standard, although the movement of some macropods such as kangaroos, which can alternate between resting their weight on their muscular tails and their two hind legs, may be an example of tripedal locomotion in animals. There are also the tripod fish. Several species of these fish rest on the ocean bottom on two rays from its two pelvic fins and one ray from its caudal fin.[3][/qs]Tripedalism - WikipediaI mean true tripedalism. But that fish is interesting and I had never heard of the parrot conjecture - still haven't.