I know it's wiki
it's strange that Reagan would build up the military and have what you claim he had. So to answer your statement it was the democrats in congress that did it.
End of the plan
Eventually political pressure to reduce the national budget deficit resulted in Congress reversing itself and passing a series of declining defense budgets beginning in 1986. Weinberger clashed with Congress over the cuts, resigning in late 1987, and was succeeded by the more pragmatic Frank Carlucci.[2] Lehman's successor as Navy Secretary, Jim Webb, remained a fierce proponent of the expanded fleet, and disagreed with Carlucci over how to cut the Navy budget in line with other services. Webb resigned rather than endorse Carlucci's cut of 16 frigates.[3] As revealed in The Reagan Diaries, Reagan reflected about Webb's resignation on February 22, 1988: "Present Sec. Webb resigned over budget cuts. I don't think Navy was sorry to see him go."
Following the dissolution of the Soviet Union in the early 1990s and the lack of a perceived threat against the United States, several of the Reagan Administration's policies and plans, such as the "600-ship Navy", were scaled back or abandoned. U.S. bases across Europe and North America were slowly decommissioned and closed, others were mothballed. In the Navy, this resulted in the retirement of several older carriers, the decommissioning of all four of the Iowa-class battleships and the cancellation of the remaining Seawolf-class submarines.
As of 2012, there are 284 ships in the U.S. Navy.[4] However, the United States still maintains the largest navy in the world, with a battle fleet tonnage greater than that of the next 13 largest navies combined.[5]
600-ship Navy - Wikipedia, the free encyclopedia