This is a pretty basic and yet complicated question. Quality is only "built in" if everything is done right, a strict process is followed, the requirements are up to a high standard, the developers understand the requirements completely, and the testers understand the requirements completely and: Test, Test, Test, and keep Testing right up until the delivery date. And even then, you may not have a Quality product.
I agree 100%.
In my organization, I'm heading up group which is focusing on establishing standards and best practices for requirements. I have over 17 years of development and I still believe garbage in garbage out applies.
Building in Quality starts with a solid Requirements process but needs a very very solid Testing Process also.