We can't make it obvious that we want to build a large, well-educated, and financially stable middle class by dumping money onto it, so we build it up by dumping money into the DoD instead
FWIW, the DoD employs 1.3MM active duty service members, 750k civilians, and 800k National Guard and Reserve service members [1]. That's about 3MM people, generously rounding up. If you consider the surrounding defense industry, that's about another 800k jobs [3], so let's super-generously round up to 4MM. Considering that there are 207MM working age people in the U.S. [2], I'd be surprised if there was broad support for the DoD primarily on the basis of the number of jobs it provides or as a welfare alternative. That's $800k a year per job created! Seems fairly inefficient as a job creation scheme given the median salary in the U.S. is about $54k a year [4].
And compared to the 4MM jobs in defense, in 2019 roughly 59MM Americans were the recipients of some sort of direct welfare program [5].
1: https://trumpadministration.archives.performance.gov/defense...
2: https://fred.stlouisfed.org/series/LFWA64TTUSM647S
3: https://www.clearedconnections.com/security-clearance-news/s...
4: https://www.thebalancemoney.com/average-salary-information-f....
5: https://www.urban.org/sites/default/files/publication/99674/...