Yes, the democratic elections conducted are recurring, you are not voting to change from a congress to lets say a czar regime...wait...scratch that.
Seriously, cost would increase if an election FOR the union representation would be recurring and who do you think would pay those costs?? Riiiggghhhtt. You, the union member would bear the burden of those costs in your dues. I also agree that the union would have virtual;ly no pwoer in negotiations. If a company would put enough money into a "dump the union" vote they can always threaten the union with that in their negotiations. The particular unions I have experience with would roll over like a beagle getting his tummy scratched.