I've learned, people of Pakistan don't follow a strategy and don't realize the realities. The 150 could've been achieved if majority of the work was done in China (as initially expected) and the assembly took place in Pakistan. Instead, they thought it would be a great idea to have Pakistan based manufacturing. Which saved billions, but brings up challenges of setting up manufacturing facilities, machines, equipment, people, training and all. Which is a crazy enough task as you are LITERALLY setting up a new industry.
People who know the JFT's mechanics and systems, also know that this plane is MUCH advanced than anything Pakistan overhauls internally, or has experienced with. Including the block 15 -16's (engineering and capability wise. Performance wise, F-16's aerodynamics are superior). So jumping from 2nd generation overhaul capability to actually trying to produce a 4th gen fighter in house (58% components, slated to go up to 80% made in Pakistan) is a HUGE under taking and will have risks. The most significant risk was the fact that the highly engineering focus facilities and skilled engineering labor wasn't there to just jump on it. You have to train people, then ensure their mistakes will be corrected by professionals.
And then a need for another facility for overhauling and export related manufacturing was also needed. Which is either done or being created as of now. So these were huge under takings, you should be proud that all this has happened and the JFT is now manufactured in Pakistan (wit majority of components).
Next, the block I was really a prototype production or proof of concept production. The PAF slowed down as they wanted their people to be trained, but also, have the advanced features come from China and readily integrated. If ALL 50 block I's had been completed few years ago, you'd have a LOT of rework to do, to integrate many weapons that are now already integrated in block II. So by slowing down the production, the PAF ensured the training of required labor force as best as possible. But yet, continue to get updates and really jump onto block II and make that a standard. So time was lost there as the advanced features (Anti-Ship, BVR, better Radar range, etc), were being tested in China.
The result is Block II capability as a standard package and it'll be added to the existing block I jets. And going forward, block III will be a build upon block II's capability. Block II gives Pakistan what it needed as a base package. Block I didn't. So it made all the sense to slow down the production and train labor, build facilities and establish components manufacturing, while things progress on capability on block II. This is actually HUGE for the Pakistani aerospace industry. You've now achieved jet aircraft manufacturing capability that a few countries on the planet has. And these jumps that eliminate decades worth of difference between Pakistan and say Sweden or another Tier II aircraft manufacturer, don't come in quick. Its a very, very complex effort.
