The cost of replacement shafts for most FWD cars today has dropped to the point where a complete shaft assembly with new or remanufactured CV joints costs little more (or in some cases no more!) than a brand new replacement joint. That's why most mechanics have gone to swapping shafts instead of replacing individual CV joints.
When the shaft is changed, your old shaft and joints are exchanged for the replacement shaft. Your old shaft is then returned to a company that specializes in shaft rebuilding. Your old shaft is then rebuilt using new or remanufactured joints. The shaft then goes back into the parts distribution pipeline and is sold to the next person who needs one. That's how the system works. It's recycling in action, and it actually saves consumers a lot of money.
Shafts for import vehicles typically cost about 30% more than those for domestic vehicles because there are more different designs of import shafts and joints (some of which can be very difficult and expensive to obtain).