I mean... vampires are a further step in human evolution.
Vampires are an utter failure. The vast majority of them end up with some debilitating madness that leads to them at best being a monster of the week and spending 99% of their time dead and sealed or some iralvent hermit fucking around in a tower somewhere accomplishing fuckall until someone notices and burns them out.
Humans in warhammer are the only reasonably sane cooperative species with a birth rate that makes surviving long term attrition even vaguely feasible. Humans suck,
humanity is a contender, almost entirely based on mental flexibility, rationality and birthrate. They are both able to work together well enough, and able to be pragmatic bastards when needed. That rationality, when combined with numbers to absorb losses, means they are
growing. Both in numbers and infrastructure. No other uncorrupted power can say that the orgers at best
might increase their unity but that will go to shit the moment their present chieftain dies, humans along have Institutional reasons for growing without having to whore out their souls to the dark gods.
Vampirism? you have a 99% chance of giving that up. You lose that sanity, that ability to corporate and be pragmatic and in exchange for what? strength? immortality? congratulations, you're a shitty demon knockoff that's traded needing to be summoned for defeat meaning you spend the next thousand years at the bottom of a deep-sea trench, and the risk of devolving into a Vargheist if you get trapped somewhere.
the elder races are strong but fading, vampires are stagnant
at best, and humanity is rising. Vampires are a mistake. A flawed byproduct of an inhuman things search for immortality. Vamprisim gives up the major advantages mankind has in a futile attempt to match the monsters of the world on their own playing field, but if mad monster where the answer the human nations would have crumbled a long
long time ago.