TL;DR
A canonical answer should continue to be rewarded, and past 10k I'm not sure that this causes any real-world problems other than a skewing of the bell curve.
Analysis
I think that this is a question that begs for a better definition of why anyone cares. There tend to be certain classes of post that should be considered:
- Posts which get a ridiculous number of upvotes like this onethis one. Was the answer really worth 2,450 rep? I don't know, but a lot of people voted for it.
- Posts that get a lot of rep very quickly.
- Posts with legs that generate a little rep over a long period of time.
On the one hand, I sympathize with the idea that a single answer should never give someone 25% of 10k privileges before they've put their time in. On the other hand, in the example used the poster currently has ~79k rep; the votes were probably earned over time, and begs the question of whether 2.5k rep (as a percentage of the person's overall rep) is even relevant at that point.
A canonical answer should continue to be rewarded, and I'm not sure that this causes any real-world problems other than a skewing of the bell curve.
Unless the chosen example is typical, and all these high-rep questions get upvoted like that in a few days or weeks, it probably just reflects longevity of the posts. Note that the post in question is almost two years old.
The current system clearly rewards time-in-grade and eyeballs attracted. With that in mind, I'm honestly not sure how per-post caps do anything but incentivize people to post more answers rather than great answers.
I wouldn't change the current system unless one can point to some valid way to differentiate "deserved" from "undeserved" rep from these sorts of posts. Fairness is a terrific goal, but I'm not sure you can create it out of statistical crowd-sourcing.
