For vampires, there were mainly three different types of evolutions they could have. A regular vampire, a vampire noble, and a vampire lord. Most vampires would remain vampires. They could train hard, try to improve, yet could never get their body to evolve to the noble level.
It was similar to humans that had just a limited amount of MC cells, or remained at a certain ability level for so long. Then there were the vampire nobles. At times there would be those that would be born with such bodies, however in other cases, there would be those that evolved into vampire nobles.
At times, there was a little help needed from the leaders, there were rituals and techniques that could bring out the energy that was stuck in their body that would allow them to move onto the next level of a vampire nobel. Of course this wouldn't work if they were just never destined to be at the vampire noble level to begin with.