I'll explain what Ushgarak said in a kid way because people will most likely still not understand.
Although you can see a certain logic in Boba Fett surviving, he did die in RotJ according to the script.
The EU has contradicted Lucas in this part, but because Lucas' personal work is more important than EU, then we will consider Lucas' original intention as canon (true).
For example: Maul obviously died in TPM but returns in a comic. If you are going to take this very serious, then this doesn't mean that Maul actually was roaming around during the rest of the SW plot.
Maul is dead according to Lucas' intention therefor the EU contradiction is overruled.
Of course the Boba Fett case wasn't as obvious as Maul's but since the original intention of Lucas was that he died: then he died.
Compare this to Mace Windu's death.. Just because we didn't see him actually die, then it doesn't mean that someone can just contradict this obvious intention by writing a silly book about it.