Is the only true path to becoming a CEO to first create a sustainable business of your own (investing money) or can you be employed as a CEO because of other experiences? Are there any good examples of this?
There are many paths to becoming a CEO. Investing your own money and building a business is not the most typical one. If we look at startups and growth companies, the typical path to CEO is advancement through various roles into a senior role in the executive team.
Some go from there to the CEO role in the same company, and many to a CEO role in a different company. People who become CEOs have typically worked in product management, marketing, sales or operations. In large companies, CFOs and GCs may become CEOs, but in smaller ones its unusual. Engineering and CTO roles rarely lead to the CEO roles, but as always there are exceptions.
The whole process starts with your own personal decision. If you decide that one day you would like to be a CEO, your mind will start preparing you for the role. You will ask yourself what experiences you will need, and then you will go out and take on roles that give you those experiences and skills. You will study and read relevant books. You will raise your hand when a managerial role opens up in your company. You will take on bigger responsibilities, you will drive for results, and you will spend time and attention on making other people successful. Those are useful steps towards a CEO role.