Why are avocados so expensive?
Supply and demand.

Supplies of avocados are declining due to droughts and unusual weather patterns. Not only drought can reduce crops, but unusual cool weather patterns can as well. Avocados dislike temperatures lower than 10°C and have absolutely no frost tolerance.

Demand for avocados is going steadily upward as more people enjoy cuisines in which they are popular, such as Mexican and many South American dishes. Avocado oil is becoming more in demand as people consume it for its healthy omegas, and cooks use it due to its high smoke-point.

Declining supply + rising demand = high prices.