The core reason why covid RNA vaccines were developed and released far quicker then a normal drug or vaccine is due to the size of the trials, especially the phase I and II trials.

Basically most infectious diseases don't really affect huge amounts of humans. Pandemics are rare.

However on the flip side is that you have small pools of people who are at risk of being infected.

However the covid pandemic massively increased the number of people at risk of being infected, especially those in the phase III trial. Consequently the efficacy of the vaccine could be easily identified.

And there were shit tons of people willing to be part of the testing.

That's why the development got super charged.

That and a huge amount of money (oh and it didn't hurt that the RNA vaccines tech had been in development for years prior. Kinda perfectly positioned for the perfect storm we faced)