Except that distributed computing via that medium is even more technically complex than vanilla-ass cluster computing. You need a way to get all that data through the botnet and back to a place where it can be manipulated, in a way that's undetectable. For a decently funded military or security/intelligence agency, spending some to buy a bunch of racks and blades and bashing a bunch of processors, ram and CGPUs together would be a more prudent investment than sneaking around and building a botnet. Obviously, this doesn't mean botnets don't have their uses.
Yeah...I reckon there's a lot of potential in appealing to the nationalism/patriotism of leading IT pers and mashing them up together in some way to benefit the nation and the integrity of it's IT networks.
Especially for smaller countries on smaller budgets.
Instead of 2 weekends a month and 2 weeks a year as a reservist, you work occasional shifts in an IT security Ops centre, cross-train others in your skillset, and upskill learning from others, stuff like that.
It's not a matter of resource.
It's a matter of these things:
1. Money. I don't have experience with Mil networks, but I have experience with government networks, and a lot of them are filled with large cumbersome obsolete technology needed to run some application developed back in 1982. How much money are you going to spend to get your infrastructure/applications up to scratch? Would you be willing to throw away all your infrastructure and start again properly - with IT security in mind? Because in some cases that's what it might take.
2. Usability. The more secure you want to make your network, the less user friendly its going to be. Is this going to impact production/missions in a negative way? One example of this is US drones sending data unencrypted due to bandwidth constraints. Having only ONE gateway to the internet for example may throttle bandwidth for all users on your network (especially remote) but it's certainly a hell of a lot more secure.
3. Technical competency. You can set up reasonably secure networks with the right money and design, but only if you have the right skills to monitor and maintain them. For that you need to attract staff on the right wage.
4. Proper management tools. Having to keep desktops, servers, etc patched and maintained can be a pain in the ass. Alerts. Deployment. Firewall management. But having the right tools makes this job a lot easier. Requires money and technical competency however to realise these tools and set them up. There are a LOT of tools coming out on the market these days that are getting very clever at managing your IT infrastructure, but they do cost a lot of money.
With the right structure, and the right tools, a smaller number of resource can effectively run a network. I'd rather pay a small number of extremely highly skill guys and have all the right gear, than loads of average skilled people (which also introduce human intelligence points of failure into your network as well).