It probably DID if "All Good Things" is any indication. In the time it takes for Beverly to get fed up with Jean Luc's bullshit, divorce him, then get her own command of a medical ship (time enough for B4 to become an oxford scholar and Riker to take command of the Enterprise-E) cloaking devices will be standard issue on Starfleet ships.
Something else to consider: the neutral zone treaty applies to Federation starships, of course... which is to say Starfleet
ships. It doesn't seem to apply to civilian ships from either side, which are doubtless subject to all kinds of invasive inspections and harsh tariffs at the neutral zone outposts. The Algeron treaty probably doesn't apply to civilians either, and certain civilian operators could probably get away with operating commercially available cloaking devices for espionage purposes. They wouldn't fool romulan or Federation sensors, of course, but they might be enough to, say, hide a holoship in a lake somewhere or fool the locals of some planet you're scamming by pretending to be the devil incarnate.