I've been on a team like that early in my career, and the results were predictable: standalone developments, poor communication, and a complete lack of shared architecture or security guidelines. The application became a monolithic mess, nearly impossible to evolve or fix. Now, of course, I would do it differently.
The common misconception is that adding more developers will automatically increase output. The reality is that without a unified direction, a team's potential is never fully realized. This is where the role of a leader becomes essential.