I usually retort that I have golf clubs but can't play golf. It's not the clubs and its not the traps. Common problems are setting good traps in bad places or bad traps in good places. You have to trap all of the moles in your lawn and not just the easy ones. Even systematic trapping may not be and end-all to a mole problem.
Moles always take the path of least resistance when tunneling.
Any neighboring mole will probably recolonize the old tunnels and you will have more trapping to do. Empty tunnels will also be used by dispersing moles in late spring and migrating moles in the fall. I seem to get this a lot especially since some questionable test results from Michigan State University were released and the concoction was allowed to be sold premixed from various manufacturers. It is now sold under names such as Mole Away. These products always list pocket gophers or gophers along with moles on the label.