The point of the site is to improve answers to solve the OP's problem. Refining answers is expected.
With comments, the whole point of comments is to improve an answer - they should be incorporated and then deleted out; they are intended to be largely temporary.
With answers, this shouldn't generally be a problem with a good question. When can you just rampantly incorporate other answers into your answer? Apparently they're not too different... Either:
- The question was a list question in the first place, which is bad
- The answer being incorporated is a crappy little answer that should probably have been a comment
- Another answer points out a minor flaw in the answer, in which case it's completely legit to fix it.
Furthermore, you should NOT post an answer when there is a very similar previous answer - you should comment/edit/refine and vote it up so that a clear community answer emerges. Nothing's worse than 24 answers all of which say "yes, with mostly the same justification!" That should be one well edited answer with 24 upvotes.
On the end the whole rep system is meant only to be an incentive, the goal is good questions and good answers - if that's happening, there's nothing wrong.