Just like USMC did with Zulu and Venom. JSF had more of political and business motives behind it as compared to defence and security.The F-35 was an attempt to put all capabilities in a single aircraft. This was a failure. The smarter approach would have been to have developed shared subsystems but different platforms that share those subsystems. This is the approach that Pakistan has taken, willingly or knowingly or not. And I believe this is the right approach.
(All assuming all this actually transpires as no solid evidence still exists. We are rightly being accused of being a gossip hotspot).
1. political motive was to keep alies engaged for more than 25-30 another years
2. Business motive was to capture 5th gen aircraft market and sabotage research in stealth aircrafts abroad