Using live culture in small doses or dead culture pathogens to produce vaccines has been the norm and has worked well for us. That's not what this Covid genetic therapy hot mess is though.
The first Chinese vaccine sinovac was a inactivated whole covid virus based vaccine. It apparently is less than 50% effective in its original dead virus form. So that route was taken right off the bat with the chicoms. The Russians tried the same route and gave up as before doing much human trials they too saw that a dead virus version is too weak to cause the same kind of immunity reaction that cowpox did for smallpox.