Another example would be an effective border control program.
Imo, those "multi hundred billion dollar defense projects" do benefit "the general welfare" but it's an indirect effect rather than a "direct deposit". One of the GW problems is often lack of competition, which drives innovation.
Spinoffs of defense projects have delivered countless benefits to the GW, ones that likely would have developed eventually but were given a kick in the pants by needing to beat the other guy.
Basically my view is that you can't be as concerned about your 'welfare" , ie "the state of doing well especially in respect to good fortune, happiness, well-being, or prosperity." until AFTER you're "free from the risk of loss". . And imo, that's a primary reason they were put in the Constitution in the order they were.
"in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity"