I agree with you and generally this is a great way for a startup to save money as well because new grads are cheap.

The problem that you'll then have though, is that when you encounter a tough technical challenge, you won't have the benefit of having someone on your team who has seen it before.

So there must be some golden ratio. A solid emphasis on college recruiting to serve immediate needs, with a focus on building out a technical knowledge base accompanied by many years of experience.