The mRNA technology is not so new actually. The vaccines ( not vaccines actually) using mRNA technology would never have gotten FDA approval if at all in their current form this quickly if not for the opportunity created by the pandemic. The mRNA vaccine was highly unstable and could not exist in the human cytoplasm for more than a few hours until researchers were able to use a lipid coating which allows for protection from degradation once inside human cells. The largest drug trial in history is under way.
HIV and Herpes are not transmitted by aerosol and are not pandemic drivers . Therefor using currently mRNA vector technologies for non pandemic disease may not afford pharmaceutical companies zero to little liability for unfortunate outcomes or the government underwriting of possible lawsuits as is the case with, Pzifer, Moderna and Johnson and Johnson for COVID-19.