A corallary would be that if you could become immortal you'd probably be bored to death.

And I think this points in the other direction- I think this suggests that 'a century is but a blink in the eye in the life of an elf' might actually be accurate. You throw some dwarves in the dungeon, then go about your normal routine, and then say 'oh, didn't we just capture some dwarves?' and it turns out that you've done your weekly routine a few thousand times since then.

That is, if you're ten times as old, you only expect a tenth the number of 'new events' during the same period, and it's likely that anything faster would lead to a feeling of change happening too quickly. Hanson's talked a bit about minds (and thus ems) ossifying, which lines up with this- if you've been practicing a particular variety of corporate law for 300 years, you're probably very good at doing that law and not very good at picking up anything else.