This is a huge flaw, but it is even more common to have the opposite huge flaw, that is, to only do the safe cash-cow things, which has killed many big companies. I believe that this is the core problem of any business with hit-miss dynamics, huge gains for single hits, (small) losses for every miss. Once you get a hit you can often monetize it for quite a while, like Disney does with all the stuff they sell related to the movies.

The dilemma in other words is: If you don't have a hit, it is hard to create one. Once you have a hit, it is easy to monetize, but will not last forever. In other words you need to both milk the cash-cow and produce new hits. It seems Valve is doing the latter excellently, but maybe they should build a separate organization for doing the former, since their inner workings is not optimal for that. Milking the cash-cow is often much less demanding, and more tolerant to mismanagement, so it should be a prime candidate for outsourcing.