Anecdotally, our three boys all were told they MUST have braces (each for different reasons). We did this for exactly none of them. And their teeth came out perfect by adulthood.
If you keep them on soft food young, the jaw muscles don't get stimulated enough to grow so that the teeth that are coming out sit properly. Misalignment and opportunity for decay ensues.
If you give them decently hard food early on in life you solve most problems.
After that it can still happen but there's less chance.