Not really sure where the S-400s and the west’s hysterics over that deal with Russia fits in. This was, if I am not mistaken, a response to the 2016 coup attempt.

I am assuming Erdogan has attempted to follow a multi-vector foreign policy - somewhat against the EU with migrants, somewhat supporting Israel to appease the US, while protecting himself from another coup attempt, not least with the presidential palace, parliament building and other locations being bombed from the air during the 2016 coup attempt, with Incirlik playing a role.