I think you're coming to a strange conclusion in what you've said...Ivermectin is out of patent - far less money can be made from it. US pharmaceutical company Merck – one of the manufacturers of patent-free Ivermectin actively discourages use of ivermectin -- Also Merck signs $356M deal to supply US with experimental coronavirus drug. These are the financial interests you should be looking at.

https://swprs.org/merck-claim-exposing-big-pharma-lobbyists/

Vaccine prices have been increasing.

https://www.brusselstimes.com/news/belgium-all-news/health/1...

Additionally, 'one $5 vaccine' is just wrong. There is already 3rd booster shots being administered in Israel with the pfizer vaccine as its effectiveness is diminished with the delta strain (and Epsilon..no doubt till Omega) ...The possibility of these vaccines being used similar to annual/bi annual flu booster shots is far from 0.

Nor is your comparison a fair one...It isn't a split between use the vaccine or have everyone require days of medical care (that would of course cost more...Not necessarily to the benefit of pharma companies though) -- IF ivermectin was a effective (even just 5%) prophylactic OR treatment/therapy against severe covid symptoms (let alone possibly doing both of these things) that certainly would affect the profits of phara companies getting contracts and sales of their patented offerings.