Why did Gombrich believe this a little history of the world would be so challenging to write?

The correct answer to this open question is the following.

Although there are no options attached, we can comment on the following.

Ernst Gombrich wrote his book "A Little History of the World" in 1935. In 2001 he committed to writing the book in English for his American and English readers because he wanted to use simple terms so kids could understand the historical events such as the first humans on the planet to World War 1. The problem was that Walter Neurath, his publisher, pressed him to end the book just in six weeks in order to publish it as soon as possible. That is why he thought it was too challenging to write.

i believe the answer is:

-   william jennings bryan is a democrat while mckinley was a republican

at that time, the segment of population that choose for democratic party were the voters with low economic background and vice versa

- william jennings has support of populists and wants to have inflation to farmers while mckinley has support of bankers and businessmen , doesn't want inflation

the fixed value of gold make the large business able to stack up their gold without   being worried that it would devaluated.

- william jennings supported the silver standard while mckinley supported the gold standard

according to jenning, using other metal beside gold could the poor people to have more purchasing power and them advance in the society.

definitely a for sure. ill see and update if i get the answer