In his rush to make a name for himself and his beloved Kenya. Leakey was a bit lax in his hastily arrived conclusions and lackadaisical manner of recording accuratly his findings and work.
The first shot came when the legitimacy of Oldoway man came into question. Instead of examining the new evidence and conceding to more up too date methods and more accurate work he held on to an increasing less tenable position for far to long. His credibility as a scientist and his reputation took a hard knock.
Then when he took skeptics to see sites of later more sensational findings in an attempt to convince them, they found glaring inconsistencies in the demarcation, recording and documenting of important finds. Once word of this got out much of his work was called into question.
Adding to this, his marriage was falling apart, due to dalliance on his part, with a young illustrator. As a result there were few who were willing to touch the now tainted scientist. There were no more jobs for him in his beloved field and he had to be satisfied with studying living people from the Kikuyu tribe.