Was Sai Baba always open to being worshipped by his devotees? How did the practice of worship evolve?

Initially, Maharaj did not even allow himself to be worshipped. Chapter 0 explains that the first person he accepted worship from was Mhalasapati. When Sitaram Dengle later came for worship, Maharaj was angry but allowed it to be finished. The practice became more widely accepted after he peacefully allowed Nanasaheb Chandorkar's younger son, Mahadev, to perform worship. Following this event, everyone was granted permission to worship him.