How did Elon Musk become the richest man in the world and what is his source of income?
Tesla sales are lower in Asia than in Bangladesh. Visit Tesla's website to find out where you live (not on the Asia list). 
As co-founder and CEO, Elon Musk (full name Elon Reeve Musk, a native of South Africa, Canada and the US, born in 1981 in Pretoria, South Africa) is a Tesla (started in 2003) car. Was. What he did for Tesla; product design, engineering and global manufacturing of the company's electric vehicles, battery products, and solar energy products (Solar Roof & Solar Panels). In addition to Tesla, he is equally involved in SpaceX, Neuralink and The Boring Company. 
Tesla ranks fifth on Wall Street after Apple, Microsoft, Amazon, and Alphabet, and has a market capitalization of around US ৮ 730 billion. However, there are rumors of over-capitalization in the market. Check out a recent chart from Tesla:
Elon Musk, the companies that run and make money without Tesla are;
Supervised the development of rockets and spacecraft at SpaceX.
CEO of Neuralink, the company is developing an ultra-high-bandwidth brain-machine interface to connect the human brain to computers.
Boring Company- which integrates fast-cost tunneling technology with an all-electric public transport system.
Hopefully you understand how Elon Reeve Musk became the owner of so much wealth.