Eric:
All three of these researchers have done a fair amount of time in academic institutes. Also, Freitag and McCallum have done groundbreaking research not just in information extraction in general, but also in information extraction with HMMs. Check out Dayne Freitag's web page to see a list of papers. Given this, I can't guarantee that the other algorithms weren't tuned perfectly, but my intuition is that these other methods were well developed and thought out (particularly the hmm methods).