It has been money well spent, but I agree with you and President Trump that we should be bringing the troops home not wasting money and lives on endless wars overseas.
Many of the key advancements were made with military funding, but: A) the fact that the military did it first doesn't mean that somebody else wouldn't have done it a year or ten later. B) how much did we waste on our main goal of murdering people, compared to the amount of funding necessary for helpful scientific advancements?
If we threw $700 billion a year at anything, we'd see major scientific advancements happening almost by accident. We could have invested it in agriculture, or infrastructure, health, or ending poverty. All of those would produce major first order benefits in addition to the advancement of science and technologies.
The technologies we got out of the space program are vast and while there was always a military aspect (there couldn't really not be given that the technology to put a satellite is basically an ICBM) a lot of the technology had civilian applications.