It takes about eight years for the agave to mature to a usable state, and when harvested the entire plant is removed from the ground, so its another eight or so years for the next one to be ready. Add that to the strict laws about where the agave has to be grown to be called "tequila". Finally factor in the aging time for the Reposados and Anejos and you quickly get to 10years.
Compare the prices of any 10+ yr old single malt to the prices of the better tequilas and they are right in line, and the single malts are just made from grain!
When I think of things this way I can easily justify the expense of the good stuff
