This is not true. Before I bought my road bike, the guy at the lbs measured me using a fit kit to determine what size frame I should get as well as other basic measurements like handlebar size. From there we picked out a couple of bikes to try, and he told me to go ride them around the neighborhood for a while to see which one I liked best. Then after I decided which one I liked, I paid him for it.

After that, we made some changes (e.g., handlebar and seat height). Over time based on specific issues we made other changes.

But I was measured before we did anything. They measured things like inseam and arm length.