
Interestingly, I'm working in the public sector too.. As an ops manager, so I have to deal with this kind of thing all the time.
We run open source quite happily in areas where it can be brought in cost effectively, and have replaced some of our old windows infrastructure with open source equivalents without the end users even knowing.
The joy of the (very overworked) staff here is that they actually keep an eye on the ball; if there's new tech, they'll experiment with it in test, judge its applicability and then roll out on pilot to see how it floats in the real world.
It's a little known process called 'Evolution'. Oh, and it applies to our technicians, systems admins and developers, all who are conversant with the main open and closed technologies from the last decade, and in some cases, a fair bit longer than that. If you're incapable of learning the best technologies for the jobs (from a limited, but slowly changing set) then you've no business being in systems ops or development.
I've been working in the IT game for a smidge over 25 years now, and the only things that'll be near the same over that time period are the Mainframe apps which steadfastly refuse to go away because they're so damnably efficient. The back end will remain the same, but open alternatives for the console apps can easily be open source on the user end, no retraining required.
Everything else has changed drastically (and does so with a period of approximately 5 years).
Despite your belief that users are there to be spoon fed every little bit, there are actually a minority like that; most of them are quite happy to pick up something new as it's phased in. That's called a normal learning process.
Due to the whole NPfIT project in the NHS, there's a huge quantity of information on the feasibility of retraining a large amount of people in a very short amount of time. It can be done, but the efficiency is over a couple of years (i.e. phasing in the new cheaper tech over time, thus new purchases should be based on 'Standards', as the report advocates, not proprietary locked in closed spec). This is more the way things would go, as ripping out the whole infrastructure overnight, as you seem to see it happening, and replacing with new would make the cost of training seem to be a small drop in the ocean.
Anyway, enough of the badgering, and end of lunch break..