Titles are a way to divide responsibility in a team.
This is beneficial in some cases, for example the CTO is responsible for technology decisions in the company which allows them to make decisions without involving everyone.
But yes, in a startup the roles overlap much more. So there's no need to divide responsibility, hence no need for specific job titles.
However in getting rid of titles you disperse the responsibility of parts of the business to more people, so more people are to blame.
A good middle ground is to have a leader and employees with multiple titles.
This is beneficial in some cases, for example the CTO is responsible for technology decisions in the company which allows them to make decisions without involving everyone.
But yes, in a startup the roles overlap much more. So there's no need to divide responsibility, hence no need for specific job titles.
However in getting rid of titles you disperse the responsibility of parts of the business to more people, so more people are to blame.
A good middle ground is to have a leader and employees with multiple titles.