I am a four-time entrepreneur who has also worked in a major corporation for several years and has consulted many others.  Yet my experiences working on both sides of the fence don't make it any easier for me to understand why big companies consistently fail to place at least small bets more adventurously when there are signs that their business model is peaking or has peaked.

Sure, Clayton Christensen outlined a lot of great reasons in his classic The Innovators Dilemma.  But my question is a little more fundamental.

When big companies have a cash flow and the wherewithal to actually make some seed investments in something new, why does it never, ever happen?  Why are things like serendipity, experimentation, and the like considered to be so awful?  Are the internal zealots shouted out by people focused on the core business?  Are executive leadership teams always more prone to act on survival than opportunity?  

New ventures are usually the things that can ultimately give the big business some assets when the old business model does indeed wither away.

Amazon is pretty good about it.  Google has been chastised for it, unfairly in my opinion.  I hear that eBay does a reasonable job.  Who else does a good job of it?  There aren't many cases.

Just something that I may never really understand.