It has happened before as part of the moves to destroy majimbo. Mboya was the architect. Like now, KANU took power without being committed to the constitution. They therefore set about dismantling it brick by brick and when done, started to create an Imperial Presidency. By 1978 when Kenyatta died, Njonjo had been mulling a bill to make Kenyatta President for Life - KANU having already so decreed.
Mboya is on record boasting that he had used his personal security to stop and remove the national flag from the car of the President of the Coast Region. Of course the title "President" was outlawed for anybody but Kenyatta. Thus Presidents of Trade Unions and Associations had to become "Chairmen" in a hurry.
The path to dictatorship in Kenya followed the same path as the destruction of Majimbo. It is that simple to understand: Under Majimbo, power was decentralized. Once you destroy Majimbo the power returns to the center.