It's a network effect, and not the good kind. The new products/existing products relationship doesn't have to be inverse -- but the organization size required for these unit volumes creates staggering complexity and inertia.

So if it ever turns out there's something about the organization itself or its structure (hypothetically speaking, of course) that's impairing your ability to put out new, different or more competitive products, you might have a very, very hard time changing it.

It's like rebuilding a car while you're driving down the road. The faster you're driving, the riskier and/or more expensive the proposition gets.

And if, for example, you build up a corporate culture which is focused around protecting those earnings and margins at all costs (again, completely hypothetical) and put in place financial incentives which reward people for doing so, you're making it even more difficult to enact large-scale change.