> Does anyone knows what's the argument to use manned planes over drones anyway?
Several reasons,
Up until now as far as I am aware there has never been a drone used in an air to air combat role in an actual conflict. There is research happening on this but it appears no one has a combat ready system. The fact appears to be that the technology is just not there yet to allow unmanned aircraft to perform an air combat role. It might not even be a technology but a cost thing, drones are cheap because they lack all the technology required for that role, they are essentially light attack aircraft, they are less like an F-16 and more like a Super Tucano, subsonic with very limited payload and no radar. The primary costs of a figher jet are related to the capabilities required for the air to air combat role, maneuverability, super sonic speed, a large radar, stealth capabilities, and missile and radar warning systems. If you tried to build drone with these characteristics you would end up with a price tag similar to a modern jet.
They are incredibly susceptible to electronic warfare [1][2].
> Turkey, which is kicked out if the F-35 program for political reasons, demonstrated huge success in battle through it's home grown drone programs.
While true you have to take into account that in all these conflicts the drones operated in a virtually uncontested airspace. The air forces of Armenia, Syria, and Libya were comprised of a few strike aircraft. The Armenian air force had available 12 Su-25[3], the Syrian insurgents targeted by Turkey had no air force, and I could not find any sources but I would bet Haftar's air-force could not have more than 20 fighter jets. The effectiveness of drones against a peer with the capability to run 24/7 air superiority missions is still questionable. Certainly a large drone force like Turkeys is a significant force multiplier that can incur outweigh costs and casualties to an opponent but not in itself sufficient to fight against an opponent with a modern air force.
In all these cases the deciding factor was not the fact the aircraft were unmanned but the fact there were aircraft with precision weapons. If Azerbaijan had 50 F-16s or A-10s the result would have likely been the same albeit at a much higher cost. Unmanned aircraft in my opinion up until now don't present a radically new proposition they merely make large scale air strike capabilities available to states that could otherwise not afford them.
> F-35's were supposed to be the stealth weapons who were to be able to penetrate Russia made air defences etc, but Turkey proved in Syria that relatively cheap drones can do just that. Before the Turkish drones, only Israel was able to hit a Russian made air defence system and that was done when it wasn't operational at that moment. During the conflicts between Azerbaijan-Armenia, Syria, Libya the Turkish made drones hunted down multiple such system and provided very impressive footage of the action.
The US air force has flown suppression of enemy air defense missions in almost all the conflicts it fought since Vietnam always against Russian made air defenses[4]. The role of the F-35 is not a new one it's just they needed an new airplane for that role[5].
> It seems to me, the 5th gen plane projects are like trying to breed the next gen horses instead of developing the automobiles.
I guess you are referring to all the loyal wingman projects that are around. I think they are being conservative given that a bet on the wrong horse would be catastrophic for them. Their approach gives them all the benefits with very little risk, they get an expendable platform, with long endurance, the characteristics of a drone, along with increased situational awareness, immediacy, and a guarantee that a successful electronic attack won't result in the complete annihilation of their force.
[1] https://eurasiantimes.com/russia-shot-down-a-total-of-nine-t...
[2] https://en.wikipedia.org/wiki/Iran%E2%80%93U.S._RQ-170_incid...
[3] https://en.wikipedia.org/wiki/Armenian_Air_Force#Aircraft
[4] https://en.wikipedia.org/wiki/Suppression_of_Enemy_Air_Defen...
[5] https://en.wikipedia.org/wiki/Wild_Weasel#Current