Actual it was trolley problem paralysis. We could've gotten a much larger sample size much earlier (and with challenge trials, in addition to other methods) to screen out the very thing you're mentioning here (VADE).
Trials were accelerated. Anyhow, the whole premise that excessively cautious American and European regulations delayed testing is flawed. This is a global problem, and there are plenty of countries with far less onerous regulatory requirements, or with less apprehensive populations more willing to volunteer. It's no coincidence that many of these trials have occurred in other countries like Brazil.
Speaking of apprehensive populations, there's another concern on the mind of health authorities--managing the next pandemic. Say a vaccine has VADE or similar ill effects on some small but substantial part of the population. Even if the overall benefit in harm reduction is clearly superior, you may end up destroying trust. Even if your regulatory authorities are cold, calculating, utilitarian, econometric philosopher-kings, the population is not. The next pandemic might be worse, or social trust might continue to tank. Maximizing the long-term utility function might require a level of risk averseness that seems irrational in the present.
Safety rules are good and valid. They are not a suicide pact, however. With a once-in-a-century global pandemic, brave volunteers should be allowed (through even earlier large-n phase 1 and 2 groups) to help expedite the safety approval of something that can save the lives of hundreds of thousands of Americans and millions of people worldwide.