Duh:

The states’ focus on vaccinating health-care workers and nursing homes has created a bottleneck, the official said.

Source: Covid vaccine: CDC to expand eligibility to everyone 65 and older

And:

LOS ANGELES (KABC) — With Los Angeles County pushing closer to the milestone of 1 million coronavirus cases, health officials have announced plans to dramatically ramp up vaccinations by expanding the eligibility list and establishing five large sites capable of administering up to 5,000 vaccine doses daily.

I suspect everyone is fine with priority vaccinations of HCWs, first responders, institutionalized elderly and certain front facing essential workers.

But after that, things get hazy – and difficult to implement. Many have oddities like putting some high risk individuals as the last to be vaccinated. Example: Those age 60-64 and not in a priority group are last to get vaccinated, while those just a year older are first in line.

Some countries – and some U.S. states – take age 50+ into consideration in their priority scheme.

Here is California’s allocation scheme: