I think you're generalizing too much yourself here, there is no distinct line between the two types you mention. I know enough programmers that are capable of d

I think you're generalizing too much yourself here, there is no distinct line between the two types you mention. I know enough programmers that are capable of doing both things you mention pretty much equally well, this seems especially the case for those with >10 years of experience. This is already indicated by the description of the first type as being able to "completely rewrite and (re)architect an existing piece of software": that imo implies being able to "fix and understand an existing system" as you describe the second type. If you program long enough, you should be able to both start from scratch and hack into existing code. Unless you're just not good enough or have some weird split personality :]