It's not just "lack of leaders." We have powerful entities - conservative news media, some religious groups (some evangelical protestant groups, and some factions in the Catholic hierarchy) and the Repubican Party - who have deliberately and aggressively sowed disinformation about the vaccines (and about COVID itsefl), and discouraged people from getting vaccinated. Why? Money and power, basically, coupled with what appears to be utter disregard for the consequences in peoples' lives. So, it's not just lack of leadership, or stubbornness, ignorance, political beliefs, or even "misinformation." It's largely due to deliberate efforts to deceive as many people as possible, for the perceived benefit of a few.
In terms of political philosophy, this is individualistic capitalism run amok. This is powerful individuals pursuing self-interest, with absolutely no regard for any "common good." And to a significant degree, it's the same philosophy at the non-powerful individual level, too - as in, "I'm young and healthy; I probably won't get sick, and if I do, it probably won't be serious - so why should I inconvenience myself, or take any risk of side effects?" The concept of public good, of obligation to community, etc., simply does not enter in. These concepts are foreign (part of what the right wing mockingly refers to as "socialist," or "European," etc.); they're "un-American" to a large chunk of our population. "Rugged individualism," which translates to not giving a damn about anybody else.