Worked my way up like everyone else. You'll never be higher on the ladder until you can do all the jobs along the way. It's a position that's built by compounding things learned over time.
Those who hang in the longest go the furthest. There are a LOT of young people in my field. Not too many old guard. Most quit looking for less work, easier hours and more pay. Those who stick around are one of two things:
1) In love with what we do every day, and gain the reward from keeping the animals.
2) Crazy and angry people who have no clue what they are doing, but have stuck around long enought to gain forced promotions.