Change (innovation) is hard to predict, and tends to happen in areas we least expect[1]. In particular, I fail to see why the people in the Free Software community would be any worse than those doing similar work in the corporate or government environment in security or other areas. In fact, there are several data points that suggest that are better in some areas.
The fallacy, I suspect, is the assumption that those supporting the "GNU vision" are a distinct group from the others, when in reality there is a lot of overlap between your three categories. A good example is IBM, who - upon remembering they are in the business of selling "solutions" and service contracts - opened up a lot their software, and participated a lot more in the FS and OSS communities.
Also, I'll mention that we should hope some version of your "GNU" future happens, at least where communications over the internet is concerned, as "proprietary" and "encryption" don't really work together if you ever want to trust it.
An alternative, vision of the future you may want to consider: most software is (and will be) fancy plumbing.
In each field, once you have the initial discoveries made (e.g. Knuth's tAoCP, the basic hydrological theories necessary to move water that we take for granted today) the rate of real discovery slows down considerably and becomes much more specialized. Innovation happens in both. New valves and fixtures are made, etc, but most of the time you just need to hire some plumber to setup your building, or you need to hire some software professional to keep your data backed up and your invoices generated properly.
To achieve this, just like how "standard parts" are far more common than proprietary parts in plumbing, having an free and open body of software to draw on makes the equivalent job in software far easier, too. I suspect this will be true with the internet and without.
None of this suggests the corporate or government players will go away - they will simply gain the benefits a free and open library as well.
[1] first paragraph: http://en.wikipedia.org/wiki/Connections_%28TV_series%29#Con...