This fascinating article in Scientific American on how immortality would affect memory would fit better in a book called Neuroscience of the Undead than Economics of the Undead. But there is a connection!
As the article observes, episodic memory, i.e., memory of autobiographical events, decays at an exponential rate over time. That means vampires will likely have a very poor memory of events that happened to them centuries ago, with the exception of key formative events from early in their lives (probably when they were still human). But non-episodic memory, defined as the memory of “skills, habits and expertise,” does not decay in this way. And that means vampires are in a position to acquire a large number of skills over their long lives: “For vampires, there is no theoretical limit on the number of skills that could be acquired to a reasonable level of competence, aside from pastimes that require being outdoors in the daylight or the use of a mirror.”
From an economic perspective, the question is what incentives vampires have to invest in human capital — which may require a different name if non-humans may acquire it. It is sometimes supposed that immortals might become lazy because they lack the spur of impending death to motivate doing things. I think that is possible. But the fact that non-episodic memory doesn’t decay (much) creates an offsetting incentive for immortals to be less lazy. The longer you stand to benefit from learning something, the greater is your incentive to learn it. That’s why it makes sense for young people to attend college, but less sense for senior citizens and the terminally ill. The vampire, looking forward to a potential endless stream of returns from new learning, has a stronger incentive than the typical human to take piano lessons, acquire a new language, master a martial art, and so forth.
However, even if the stream of benefits from a new skill is infinite, the value of that stream is not. While vampires might discount the future less than humans (a subject discussed in Fabien Medvecky’s chapter in Economics of the Undead), they would probably still discount to some degree. Consequently, the perceived benefits of skills in the future — much like episodic memories of the past — diminish with distance from the present. The expected present value of the stream of benefits from a new skill would therefore be finite (see here for the math). Thus, while vampires would have a greater incentives than humans to acquire new skills, the incentives would not be infinitely great.