Sure, larger businesses have more developers to get more work done. But there comes a time when throwing new developers at a problem convolutes the process and actually slows things down more than it helps.

Something that seems simple to you like a flashlight attachment may not be so simple under the hood.

Solo indie devs have an advantage because they're familiar with all of the code. They're the ones that wrote it.

They don't need to learn a new part of the code when making fixes or changes. They don't need to explain to another dev that "you don't change how this information is passed in here because you'll need it to look just like that in some other section that you'll never touch".

Additionally any decisions/changes/etc. are all decided by one person, no need for meetings to get everyone on board and explain exactly what you want to do. No need to try to get everyone to understand your vision for what you want to happen.

A famous comic might explain this process a little better: