I agree completely, but note that demand can grow extremely high due to the very low cost of reproducing (and recently also distributing and marketing) software.

Supply can be limited severely by an early mover advantage, as the cost of software development can become extremely high due to the even more extreme demand. In a way this results in artificial scarcity.

Add in open source (free) software as building blocks, and venture capital, and things become even more complicated. I am sure that we need better economic models to avoid some companies to grow excessively big.