Both do better with prep time, but a sufficiently high level 5e wizard only needs the components for one casting of simulacrum to win guaranteed. First, take their components and cast Demiplane to hide in. If timing mattered, Dispel Magic on the door would cut the 1 hour duration short, preventing the military from doing anything about it. Take a Long Rest, then use Wish to duplicate the effects of Simulacrum, granting a copy that is missing it's 9th level slot. Take another long rest (24 hours, since we just did that). Then, give the copy the components for a standard casting of Simulacrum, targeting you.
Once your second simulacrum is complete, it can use Wish to cast simulacrum again, targeting you, and that copy can do it again, and again, filling up your 30-foot demiplane. Have the first simulacrum cast Magnificent Mansion, and have the chain of simulacrums fill that, too. Finally, command all but the most recent Simulacrums to leave, getting that most recent one to cast Demiplane again, and send them into the world to fight the military.
Based on spacing rules, the mansion fits 200 people, and the demiplane fits 36. Squeezing ought to fit more, but that's 234 simulacra released on the military, so we're probably fine. With you and that last simulacra remaining behind to repeat the loop, it would take 23.4 minutes to refill the demiplane/mansion area, and then release another 200+ wizards into the world all over again.
Honestly, I looked into new 5e rules for this, expecting them to update things, but besides simulacrum having a legacy tag, this exploit just... Still exists.
As a bonus, you could retain the 16 most recent simulacra, have the only one with Wish still cast it to instead create a 25,000 gp pouch of ruby dust, then distribute it, and have all of them do a proper casting of simulacrum. After 12 hours, you'll have 16 new wish-capable simulacra, reducing the time it takes to fill the demiplane to about a minute and a half. If you do this again, you could get it so half of the space is filled with simulacra that still have Wish, they all cast it as an action, filling the other half of the space, and then all head off to war, making a simulacra machine that creates 100+ wizards a second.
For comparison, that's faster than the birth rate of the whole world, and dimensional shenanigans keep you safe from missiles, nukes, and the like. Even if they broke in as people were exiting, you and one wish-capable copy could just shut the magnificent mansion door and Gate out back onto earth on a different continent, then start again easily.