When buying a pair of new tires for a car, it is presumed they are better than the (worn) tires being replaced. Isn't steering better when you put them on the front? Why is it recommended to put the new tires on the rear axle?
As a general rule tires with the more tread should always be placed on the front axle because they wear out faster for the aforementioned reasons, and when you keep the higher tread in front they wear evenly, hence the recommended tire rotation every 6000 miles. However Michelin tire reportedly warns that new tires should be placed on rear axle for fear of spin-out in case of hydroplaning, as explained @ tiretrack.com https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=52. This however is only true if there is significantly more tread on the new tires than the old (in which case the same would apply even if all were old just with such difference) however if there not such a difference place the more tread on front. Bottom line theoretically you are correct that the sensible thing is to put new tires on front from a practical standpoint, for safety reasons though it's not recommended
This is recommended because a front wheel slip is easier to correct, and more intuitive to correct for people who haven't had antislip training than a rear wheel slip.
- front wheel slip: reduce throttle, slip reduces
- rear wheel slip: steer in exactly the correct direction within a split second or you end up in a high-speed spin with the car taking up 3 lanes of traffic.
Just to clarify a couple of things mentioned in other answers and summarize some comments...
Safety... This is why many places recommend placing new tires in the rear. The Michelin recommendation mentioned by precise is concise; I had not heard of that one before. There are other safety-related reasons also.
Steering... "better" is subjective, but many people do prefer steering with new tires in the front. (Me, not so much.)