He's saying that it's the combination of COVID-19 and other illnesses that cause fatalities. Getting COVID-19 on its own won't kill the majority.
> The medical advancements in the last 100 years increased the survival chances of many who would not be here already, if not said advancements.
Ie "those people wouldn't be here if not for the reasons that let them be here", ie tautological bullshit. Guess what, they also wouldn't be dead if not for COVID-19.
Saying "x wouldn't happen if not for the thing that caused it to happen" isn't some profound statement.