America's 2023 Covid booster rollout has been slow and uneven because it works like the rest of our health care system now (whereas before it was a single-payer program run by the US government). https://www.statnews.com/2023/09/26/rollout-of-covid-vaccines-is-bumpy-but-not-unexpected-experts-say/
Rollout of Covid vaccines is bumpy, but not unexpected, experts say

The latest rollout of Covid vaccines has been bumpy — but not unexpected — experts say.

STAT