Google succeeded by combining high quality software engineering with cutting edge computer science research and beyond state-of-the-art data center operations.
Apple succeeded by combining solid software engineering with equally solid internet services engineering and more than anything exceptional design and aesthetics.
Amazon succeeded by combining solid web development with state of the art inventory management and fulfillment processes.
It's easy to do one thing well, there are literally millions of talented people in the world who can do one thing exceptionally well. But to be a company like Google, Amazon, or Apple you need to have a combination of talents that are typically unusual or difficult to keep together.
There are so many tech companies out there who have a band full of guitarists who all have the same musical tastes and background and they wonder why they haven't conquered the world yet.