Are you asking which countries had the industrial capability to build large numbers of submarines, or which nations had the strategic imperative to launch attacks on another nation's food and trade supplies, or which nations might defy international agreements to declare unrestricted submarine warfare? They aren't quite all the same thing.

Britain, for example, certainly could have built huge numbers of submarines instead of dreadnoughts, but it had no need to use those to interdict German trade as the Grand Fleet already was doing so. Similarly, America could have built large numbers of subs, but for use against whom?

Germany was essentially the only nation able to build large numbers of submarines, for use against an enemy's trade, that was also desperate enough to declare USW as a gamble that might win the war.