“The scheme to budget/spend enough to support two wars simultaneously was developed decades ago & is severely outdated.”
It is not outdated at all. Suppose NKorea attacks SKorea and China attempts to invade Taiwan? Not to mention a miscalculation on Russia’s part by invading a NATO Baltic country. Peace comes through strength and it is the first responsibility of a government to its people.
You mentioned Afghanistan. Do you really think that was an adventure and was not a correct response after AQ hit the US and killed 3,000 Americans?
The problem was not with the initial invasion & occupation. We accomplished our goal years ago & are now bogged down in a quagmire of nation-building that has lasted longer than the Civil War, WWI & WWII combined.
It's long past time to get out (but a lot of people are getting rich off the continuing occupation).