[fao_]

As far as I can tell, it comes down to two things:

a) Authors need to be published in certain journals to have their work read by their peers, and gain credibility.

b) Academic journals (Elsevier, etc.) require you to hand over the rights to the paper to them.

[dr_zoidberg]

a) Luckily in my field, most prestige comes from the DFRWS[0], which is open. And working on/with certain tools, most of which are also FLOSS.

b) As I understand, in my country it's impossible for an author to loose rights over his own work. However, I'm not a lawyer and can't give more specific details.

[0] http://www.dfrws.org/