It’s often difficult to conceptualize large numbers — something that allows statistics dealing with large numbers to convey something other than reality. I think I heard Trump say the government is ready to vaccinate 200k people a day. That sounds like a lot of people (it is a lot of people), but there are a lot of people in the US: an estimated 328.2 million according to a quick Google search.
That’s four and a half years to vaccinate the current population of the US at 200k a day, every day. Which doesn’t take into account new people being born (or aging into the range where a vaccine is administered). The CDC shows 3.79 million births in 2018 — of course that number changes every year, and it’s been decreasing. But at 3.5 million births per year, new people still add a few months to the vaccination timeline. About four and three quarter years to vaccinate the US population. And that assumes a one-dose vaccine. Administering two doses to everyone, at 200k people per year, would take just under ten years. Saying ‘it could take us five years to vaccinate everyone’ isn’t nearly as impressive sounding as ‘we can administer 200,000 vaccines each day’ — but it’s the same thing.