How is it that the Prophet Muhammad (peace be upon him) did not appoint anyone as his successor, he who does not speak from caprice, and why did he not consider that, similar to what founders of institutions do in appointing those who succeed them?

The Prophet, peace and blessings be upon him, did not explicitly appoint a successor according to the sound opinion. However, he guided the Muslims to Abu Bakr, directed them towards him, and was pleased with him. He had resolved to write a covenant for him regarding the caliphate but then abandoned the idea, knowing that the Muslims would unite upon him, as the Prophet, peace and blessings be upon him, said: "Allah and the believers refuse anyone but Abu Bakr." Thus, the consensus of the believers on Abu Bakr after the Prophet's satisfaction is stronger than an explicit designation of his caliphate. The omission of an explicit designation was to affirm the Muslims' right to choose their ruler.