In fast growing startups, there are people who can hack they way out of most problems quickly. Such people are immensely useful during the exploratory phase and early growth phase.
If the startup continue on their growth trajectory into next hyper growth phase, they need deep systems thinkers to build better end to end systems that can deal with the inevitable product complexity, org growth and user growth.
They obviously cannot build complex systems all by themselves. They need that team of hackers to believe in and execute their systems vision. They are usually good at selling their vision to the hackers as well as to the org leadership.
In really successful startups that become unicorns and beyond, there are also great visionary org leaders who can curate and evolve harmonious and motivated teams that execute well to keep pace with the growth of the company.
Of course, while in middle of it all, it feels very chaotic and out of control.