You need to buy all the intermediate steps too.
And just in case, the ticket just unlocks the respective tier, it does not *set* your crafting skill to that level, so you need to level up by crafting yourself, it just enables to ultimately get all skills to 100 on a single character if you so desire.
A legendary ticket will allow you to level another skill from 80-100. It does not enable you to reach 80 with a skill that is locked at 20 because all other slots are filled.