> They apparently settled on the the sequences for the original covid vacs in a weekend. Going from that design to billions of doses is one of the hardest things to do, but once done, will persist.

No no. They had a candidate for the vaccine. Scaling manufacturing is hard, sure, but the actual barrier was proving the candidate worked. We conducted (by far) the most time-efficient clinical trials in history to prove the vaccines were safe and effective.

Until that happened, we could not have known the candidate drug was actually correct.