Having a few engineers and scientists isn't good enough.
India has millions of highly respected scientists and engineers, yet India as whole doesn't have a strong manufacturing industry to manufacture what these engineers design. Ironically, Indian engineers and scientists do not shine in India, but in the US.
There is no industrial base for Saudi Arabia to manufacture what its engineers put out. This is why a Saudi jet fighter is impossible at this time, and only a handful of highly industrialized nations are capable of building their own indigenous jet fighters.
I will give an example. China has transferred JF-17 technology to Pakistan. Does that mean Pakistan can now go out and build its own indigenous fighter jet that could be called Pakistani? The answer is no.
With all due respect my friend - you were talking about the Pakistani JFT project, which is why I responded with info about that, and Pakistan's indigenous aeronautics industry as well. Perhaps you forgot.
Anyways, I do agree with you that this takes a certain level of industrial development. Even some of the most technologically advanced countries on the planet can't build their own aircraft(without foreign help). Saudia Arabia isn't making it's own jet, it's industry isn't there yet. Point was that it seems to be having a modern industrial-revolution fueled by hundreds of billions of investment in various sectors of it's economy.
I don't know about the Korean F/A-50(if that's what it's still called - I heard it's name got changed?), but about the Swedish JAS-39, the engine isn't the only thing they import. In general with avionics, radars and missiles go together - like if your radar is US-origin, it'll work with AIM-9 Sidewinders and AIM-120 AMRAAMs. If it's Russian-origin, you get R-73 heat-seekers and R-77 radar-guided missiles. Sweden had gotten the British GEC-Marconi to develop a large part of it's avionics suite including the radar, due to which the aircraft works with Euro weaponry like the IRIS-T(which they also import, and have no local counterpart) works. And they did pair older 70's era AIM-9Ls, which are simpler to integrate(Pakistan's Aeronautics industry also integrated these with JF-17s, F-6s, F-7s, giving them more of a "punch"). That's why a % is calculated to show how much is made locally, while the Swedes have been making fighter aircraft for decades(Viggens, Gripens, etc), a significant minority of their components are still imported. Since Pakistan and Korea are doing their first combat aircraft it is likely that this % is higher. Pakistan is getting TOT(Transfer of Technology) from China, Korea would get that from the US. Debatably, China is more open with their tech, the US doesn't give alot even to the EU(5% of Eurofighter components still US-dependant), however US tech is more advanced than China's at the moment. I don't think Korea is planning on making it's own range of air-to-air, air-to-surface, heat-seeking, radar-guided missiles, so some avionics would likely be imported too, like the Swedes.
And the Israeli Lavi was different because not only were they importing, they were also funding the project with US assistance. Even now a number of Israeli politicians criticize the closing of the Lavi project, and say that some Israeli lobbying could have kept US funding flowing, despite the aircraft being an F-16 competitor.
So while there are only two or three countries capable of going the whole 9 yards on their own, many others achieve varying degrees of indigenous capabilities. KSA seems to be in the process of revamping up theirs, with oodles of $$$ and them paying to have avionics and sub-component manufacturing in KSA, they seem to be able to make rapid progress.