> "Bellard doesn’t appear to promote himself—he politely declined to be interviewed for this profile"
In my opinion, that's the key.
Getting famous, comes in the way of a lot of people, whether they are a scientist or a programmer.
Read at some place, that many popular scientists, once they do something great and get popular, just have to interact with other people so much, that they don't get the time for doing something great.
Recently, on HN, there was a 'letter of note' by some famous author of why he was going to stop replying to reader letters. As that left him no time to write another novel/story[1].
Of course, for mere mortals (who don't taste that level of famousness) there are mundane hindrances like Facebook ;-)
[1] Discussion on 'The morning mail is my enemy' http://news.ycombinator.com/item?id=4409363
Update: Added reference