Since the 1970 merger, only three quarterbacks who were 1st round picks started three or more opening days before their 30th birthday and were not in the NFL a year after making the last of those week 1 starts.+ One went to the USFL (Doug Williams); another ended up in jail (Mike Vick).
Josh Freeman is the other.
Freeman isn't giving interviews and the teams aren't providing insight into why Freeman is now a pariah, so I'll speculate as to why that is: Perhaps Freeman entered his final season in Tampa unhappy he didn’t get an extension, and that bad attitude he displayed hurt his reputation and soured teams on him. After all, the only team that gave him a chance once Tampa Bay cut hm was Minnesota, and they were desperate. (It kinda makes you wonder why the Rams, Jets or Texans haven't contacted him, doesn't it?)
Or maybe we’re just in a period where teams are only keeping two QBs on the roster, not three, as has been the case in years past.