Dont understand.
Ok I must admit didnt know I can reserch say jet fighters infinitely..still..
What models you are getting after last tech level in game?
What is the reference?
Besides,after more than one power obtains nuclear weapon, geopolithicaly should became status of stalemate-cold war,in which global conflict is impossible,only smal local conflicts ...or total nuclear Annihilation.
Even in HOI II I didnt played post 1948 era global war prolongation,considdering it geoplithicaly impossible.
Though I believe can serve as sandbox exhibition.