Because the United States was at peace during the Reagan administration it was unnecessary to raise military spending then. Military spending should have been reduced.Hector, your timeline for balancing the budget is correct, but your assumption of why they were able to is in error.
The ability to balance the budget was called "the peace dividend!" Because Reagan increased the budget for the military, created the phony star wars program, which basically put the USSR out of business as they headed towards glasnost and diversification, military spending fell dramatically as we were the sole world super power. The peace dividend was real, and of course congress spent it faster than it came in, lol. I am hoping that the new DOGE program fixes all that, but I won't hold my breath!