For the budget minded crowd, China is becoming a major supplier. Russia offers slightly more upscale stuff, and several other nations, like India and Brazil, are also moving into the bargain basement weapons market. The U.S. and Europe still sell the top of the line stuff, for those who can afford it.
But something else is happening. This massive market for replacement equipment comes at a time when a lot of new technology is coming on the market as well. This is especially true in the case of sensors and computers. Lots of new materials as well, especially lightweight, sturdy stuff that is bulletproof. There is an opportunity for radical new weapons designs, because of this confluence of market demand and new technologies. There will be, actually there already are, more effective and cheaper missiles. Robots are appearing in large numbers, for air, land and naval warfare.
A lot of this stuff is cheap, at least cheap as modern weapons go. But these exotic new systems are also relatively untried. The next decade will see a lot of procurement activity, and the items being bought will be new designs. It's going to be interesting.
Two major American military systems are going out of service. The C-141, the heavy air transport that provided the bulk of American airlift throughout the Cold War, and the Spruance class destroyers, are being retired. The Spruance was a major breakthrough in surface warship design. The Spruance design marked a break with the World War II warships that provided the bulk of American naval power for two decades after World War II. Same with the C-141, a modern, four engine jet transport that could move just about anything, anywhere. The larger, and less successful, C-5 came later, but the C-141 carried most of the load. The C-5s are also entering the end of their useful lives. In fact, most of the Cold War era weapons and equipment are wearing out. When the Cold War ended, the most heavily armed region (Europe) disarmed to a large degree, and sold off their surplus stuff. Many nations have been living off Cold War surplus for the last decade, Europe, especially Russia and East European nations, sold off their unneeded equipment cheap. Even the United States had a lot of gear if didn't need, as it disbanded about a third of its armed forces. With surplus gone, and not much new gear produced in the last decade, there is a growing demand for replacement weapons and equipment.