Actually, as far as I can see, the main factors delaying testing of vaccines (or indeed any medication) are:-
1. Cost - testing with real people as opposed to rats is very expensive, you have to inject and follow up a wide range of volunteers. A lot easier to find the volunteers and the money/staff in a pandemic.
2. Risk aversion - and I don't mean aversion to the risk of harm to people - I mean aversion to risking money on a product that may not pay off. Again, a lot easier to justify during a pandemic, when you can carry out tests at the same time instead of in sequence, and tool up for production without even knowing whether you have a viable product. (and with any sort of luck someone else will take the risk, for example the government or philanthropists)

