Is there a consensus as to why Trump cycled certain people through being Director of the C_A?

Let's take a look at the timetables and the players involved here.

Gina Haspel- Deputy Director of the C_A 2/2/17 to 5/21/18 (1y3mo). Became acting Director to replace Pompeo for a month, and now actively holds the position.

For reference, most of the previous Deputy directors served for ~3 years. One exception being being David Cohen.

David Cohen- Appointed by Obama, did about 2 years before fired/resigned on 1/20/17. Previously was the Under Secretary of the Treasury for Terrorism and Financial Intelligence (4y) and before that Assistant Secretary for Terrorist Financing (2y).

Who was also fired/resigned on 1/20/17? John Brennan.

Succeeded by Mike Pompeo, who did 1y3mo as well. [15] months.

Mike Pompeo- attorney and former Army officer. Was on the Kansas House of Representatives for 6y before being instated as Director 3 days after Brennan was fired.

Every other Director since 2005 had worked with some sort of intelliegence agency or committee before becoming Director. House of Reps to Director? Never happened before. [TRUST KANSAS]

Now he is Secretary of State.

Why have him assume leadership of the C_A before SoS?

How would that position help prepare him for his role?