Disclaimer: I have no qualifications or really any business talking about this…
I think games aren’t the best kind of projects for open source. Some games are made open source after development ends which is cool because it opens up forks and modding (pixel dungeon did this). Most games require a single, unified, creative vision which is hard to get from an “anyone can help” contribution style. Most open source software are tools for doing specific things. It’s almost objective what needs to be done to improve the software while games are much more opinionated and fuzzy. So many times I’ve seen a game’s community rally behind a suggestion to address a problem and the developer ignores them and implements a better idea to more elegantly solve it. Most people aren’t game designers but they feel like they could be.
An exception to this are certain, rules-based puzzly games. Bit-Burner is an open source hacking game with relatively simple mechanics and it works well.
I’m not sure how serious your comment is but anyway…what you’re describing is a decades-long reorientation of military doctrine and procurement strategy. Getting a different multi-role fighter is already a huge expense with lots of ramifications but no need to throw the baby out with the bath water.
Edit: IMO, if you really wanted to alter air force strategy to deter the US, you should look to Sweden and Finland who have been facing an asymmetric threat for decades. Aquire the Gripen, train with the Swedes in how to run and operate a distributed air force of small independent units capable of generating and performing missions from random roads in the woods.