Not all military boots are steel toed, and in some cases, especially the infantry, you don’t want steel toe boots. When I was in the marine corps, steel toe boots were more expensive, and significantly heavier. Weight plays a huge factor, and in the field, you never really have to worry about large equipment falling on your feet to need the steel toe, especially since the standard boot is typically rugged enough. Nowadays they even have what’s called a RAT boot which has heavy leather to reinforce the toe instead. However, in some cases they are helpful, if you work in motor transportation, supply, or comms, most of the time you are working in some kind of garage or warehouse.