theoretically right. But how many countries are independently manufacturing jets acceptable to most customers , in areas of serious present or potential conflict ?But another country can join TFX program.Then it will not only fasten the development of NGFA but also divide the cost of development work.
Turkey's main enemy is Greek which is a small country and can't afford 5gen.fighter jets in large numbers.So Turks have time to properly work on their TFX.
European union ( in this only uk and Germany have the technical skill to go at it alone )
China - not many exports
Japan has the skill but it uses American engines
Getting a fighter off the ground is not so hard. But to make a complete package, which is a modern deterrence or threat , is a different ball game.
And I recall reading that Turkey has asked the usa for more f16s ?