Although most companies treading the open source waters probably won' t go the route of strictly GPL'd licensing, a lot are coming up up with variations of that type of license, most because they're worried about having the final say in what bugfixes and features are incorpoated into the products.
Some projects are soley internet based and set up to be non-profit from the beginning.
Lower development costs, true worldwide peer review, quicker bugfixes and tweaking done by source hackers unmatched by proprietary software vendors who shall remain nameless. Every company makes errors.