We spend trillions of dollars on all things military.
Well, we live in a dangerous world. Russia, Iran, China are strategic adversaries. Russia is waging war against Ukraine, and if successful may extend it elsewhere. Iran is, through its vassals, de-facto occupying Lebanon, Yemen and Gaza, and is working on obtaining nuclear weapons. China has eyes on Taiwan (although I think Outer Manchuria would be a better target for them). A strong military is a necessity.
Why couldn't a lot of that money be turned around and spent on universal healthcare, university education for all, maternity leave for mothers, ect?
US already spends much more on social programs than on military.
Medicare alone is almost as costly as the entire defense budget. And you want to cut it more to fund even more social programs?
Also, why "university education for all"? Not everybody is university material. And colleges have been dumbed down too much already, esp. since the Pandemic. We do not need even more marginal students taking remedial classes.
In countries with free (for students) university education like Germany, access is controlled and only a minority of high school graduates may matriculate.
It seems the people who own and benefit most from military spending could retool their businesses or invest in such ways they could still make their money but it benefit society over all.
As I said, strong military benefits society as well, since we live in a dangerous world. And bilby is right. That money does not just go poof. It pays those directly employed by the federal government, both soldiers and civilian employees. It pays employees of defense contractors and their suppliers. And yes, the defense contractor companies make profits. But a lot of regular people own stock in those companies.