I don't know, there may be some truth to it. Based on the information I can gather, it seems Bellard's LTE implementation (linked yesterday) was completed over the course of about a year in his spare time. I don't know many programmers that can keep that kind of pace.

If it encompasses more than just the time of writing code, it becomes even more believable. e.g. A great programmer will take a day to implement the given feature and it will be relatively bug free. An average programmer will take a day to implement the given feature and then it will take another nine to work out the bugs introduced.