I think you can actually do a lot with average people, if you have sufficient structure, process, guard rails, documentation, training and reviews. And big companies have a lot of this, specifically put in place to harvest above-average work from average talent. Yes, a company full of John Carmacks, un-shackled by process, can probably run circles around an average tech giant, but who can actually find and hire all these John Carmacks?

A steady state calls for steady people.

The concept applies everywhere. The most skilled painter of art is probably not the best person to paint your living room.

its risky for big companies to move quickly. They mostly want to maintain what they have. its a myth that they want to innovate daily

Big companies 100% focus on maintaining their products/position, relying on acquisitions for innovation.