"We didnt get the F35 because of the S400, but even then they would not give it to us because of (insert some random mumbo-jumbo)" is such a weak argument. No substance at all imo. Its a deeply apologetic argument in defense of the (bad) decision makers with no meat on the bone.
It's entirely speculation, there was no indication of an embargo - Turkish pilots were actually in training.
Its always been my belief that s400 was brought because of the quagmire in Syria. When AK party joined the american/isreali war against Assad they never ever suspected that the NATO forces would side line Turkey over it and instead build up the PKK project.
Even today the western media refers to the arabs/kurds who fled the assad regime and the ypg as hired gunmen, meaning terrorists. They used Turkey to get the syrian war cooking and then took a big shit all over Turkey and demonised Turkey as the bad guy, even assad and iran when talking about Turkey were shown as allies with the west in the fight against isis, while Turkey was portrayed as the patron of Isis. What a disaster erdogan created for Turkey.
The reasoning i think ak party used, was that if we buy the s400 from Russia the Russians would give Turkey concessions in Syria, meanwhile the Americans seeing the Turks were serious would back down from their support of the ypg in fear of Turkey siding even more with Russia. Because after all would you really want trade a nation like Turkey for bunch of marxist terrorists?
However;
It was another typically short sighted AK party move. What happened was this, by buying the s400 it caused the west to double down against Turkey and support Turkeys rivals harder, the Russians seeing that Turkey was becoming Isolated from her western allies felt so confident that they could even openly bomb Turkish troops. The s400 deal was a lose lose situation. We lost f35 and got a terrible air defence system instead. We lost leverage in the western camp and gave Russia more leverage against Turkey.
Despite all this political failure, what has kept Turkey alive and what has elevated Turkey has been her domestic military developments and the performance of her army.
After the Russians killed the Turkish troops the idlib retaliation showed the world a new devastating style of warfare. It elevated the Turkish image in the space of a couple of days what 20 years of AK party rule couldn't do.
Then we jumped to Libya, by all accounts that should have been game over for the Libyan government. Haftar had russian wagnar terrorists about 10,000 fighting for him, French support and Gulf financing, haftars armies were in the streets of tripoli. Yet the moment Turkey got involved with a token force of drones, they smashed that plan and saved the government.
Then the Armenians were talking about a greater Armenia and it forced Turkey to give up on finding a peaceful solution to the occupied Azeri lands and instead throw her full support behind Azerbaijan, we all know what happened Armenia was crushed and for the first time the Russian style of mainting frozen conflicts was broken.
While all this was happening Turkey was selling drones to Ukraine and despite threats from the USA, EU and Russia not to arm Ukraine, Turkey did and as we all know the Russian invasion has been a complete disaster for Putin. It may have even been the Ukrainian drone strikes on donbas separatists/terrorists that made Russia panic and invade sooner rather then later fearing that if Ukraine becomes too armed it would be too late.
So long story short politically we have been a complete failure, yet everywhere we have been able to leverage the Turkish military we have made gains. the Turkish aim should be to find opportunities to leverage the Turkish military, discussions for us are no good, nothing can be won from it. But anywhere Turkey can employ her military to make gains, she has to. Just like in Ethiopia Turkish drone support saved that government and that state will now look out for Turkish interests.
And i guess in a long winded way Turkish military developments completely hinge on geopolitical issues, Turkey has to find a way to decouple the two issues. Turkey cannot keep worrying that if she fights to protect herself that it means the tools she needs to buy are now banned to her. And she cannot be a situation where we can buy everything we need to protect ourselves but we are not able to fight.
We need balanced decision making that understands the long term consequences of any decisions we make. S400 was brought and it was a complete failure. the Turkish position means that we have no real win win situations, every decision has a cost but that cost has to be calculated in advance and the state must know whether it can be endured and should it be endured is the outcome worth it.
Ultimately its a time game for Turkey until she reaches a position where her domestic developments shield her from 3rd party sanctions and embargoes.