Upvote:9
The premise of your question is false. Here's a brief (and incomplete) list of current jet engine manufacturers:
MTU Aero Engines (Germany)
Jet engines are their main product, usually in conjuction with other manufacturers and/or manufacturing consortiums. They hold 33% of the development share and 30% of the production share of EUROJET Turbo GmbH, 40% of Turbo Union and 25.25% of International Aero Engines AG.
Avio Group (Italy)
They manufacture a series of civil and military engines, and hold 21% of the development share and 19.5% of the production share of EUROJET Turbo GmbH. They also hold 20% of Turbo Union
Industria de Turbo Propulsores (Spain)
Sener Aeroespacial (Spain) owns the majority (53.125%) of ITP, the rest (46.875%) is owned by Rolls-Royce (UK). ITP holds 13% of the development share and 16% of the production share of EUROJET Turbo GmbH.
Kawasaki Aerospace Company (Japan)
A couple of examples of their recent work are the XP-1, the C-1 and the C-2 military aircrafts. They are part of the Japanese Aero Engine Corporation consortium through their parent company, Kawasaki Heavy Industries, and thus also part of International Aero Engines.
IHI Corporation (Japan)
They've designed and developed a variety of jet engines, a recent example of an engine solely developed by IHI is the F7 turbofan engine. They are also part of the Japanese Aero Engine Corporation consortium (and thus part of International Aero Engines).
Mitsubishi Heavy Industries (Japan)
They seem to be doing everything related to aerospace. Couldn't find specific mentions of recent jet engines they've build, but since they build Japan's main rockets (the H-IIA and H-IIB), I guess they deserve a honourable mention. They are also part of the Japanese Aero Engine Corporation consortium (and thus part of International Aero Engines).
Ivchenko-Progress ZMKB (Ukraine)
They manufacture a variety of turbofan, turboshaft, turboprop, and propfan engines.
TAI (Turkey)
They build GE F110 engines under license from General Electric, and they've also build at least one jet engine powered UAVs, the ŞİMŞEK. A (perhaps) weak example.
Hellenic Aerospace Industry (Greece)
The E1-79 ΠΗΓΑΣΟΣ (Pegasus) UAV is jet powered and was solely designed and developed by HAI. The project is now part of the Dassault nEUROn. Another (perhaps) weak example, but couldn't resist my Greek pride ;P
I have no idea why jet engine manufacturing (or lack of) would be connected to WW2, at least in the way you seem to imply. In any case, several companies that are based in the losing side of WW2 are key players in aerospace and if they build rockets, satellites and space station components, who cares if they are building jet engines or not.