I think an interesting business question is: when does a startup shift from being highly customer/usability focused to focused on making money? We've seen many companies start off by creating innovative products, and now they all just seem like cash grabs. Amazon, Google, Microsoft, Apple, Nike, etc.
Do they start to become constrained by marketing? i.e. their actual innovation won't earn them many more sales, and only by marketing more they can increase sales? Do all companies that get big enough (in revenue) do this?