Fauci was talking 3-5 years for a vaccine. Keeps Fauci in power, prolongs pandemic measures to control the population, and increases price of vaccine when introduced. Roll it out slow, so high demand low supply.
Trump ordered all of it on a speculative basis, then gave it away. Could be futures market like, but I'm not at all a finance person, so I don't know for sure, but something along the lines of a speculative price that would be lower the longer it took to release the vaccine to the public. This took out Fauci's scheme and gave the population some much needed hope.
I think Fauci was in on a scam to release viruses, then sell vaccines. Trump undercut them and also, while recommending it, said it should be voluntary, which further reduced potential profits.