Interesting, my experience is that almost all carts get the job done* but have a small amount of pull, usually insignificant enough that it can be compensated for by pushing out at one end of the handle. My recollection is probably biased but it seems pretty rare that I get a "perfect" cart. Might be down to the different stores having different carts and maintenance approaches.
*this one fact probably goes a long way towards explaining why they don't get fixed
