If Covid had a higher fatality rate, there's an excellent chance we'd have seen vaccines in accelerated trials as early as March 2020. The vaccines were in existence by around that point[0], but in part because mRNA vaccines are a brand new technology there wasn't as much push to accelerate distribution as there could have been.

If the fatality or long term damage rate was 10x what it is, there'd have been a lot more willingness to "try it NOW."

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8071766/ - of note, Moderna had a vaccine prepared 42 days after the spike protein sequence was published on January 10. It took roughly another 6 weeks before that vaccine was being injected in Phase 1 trials in early May.