>The fundamental problem is that there's just way too much heterogeneity for senior leadership to possibly understand all the company's lines of business. Which means that it's impossible to make thoughtful, intentional decisions about all of it at the corporate level.

Enormous Japanese and Korean companies don't seem to have this trouble, and they're far more heterogeneous than any American company. Yamaha for instance makes boat engines and high-end pianos and audio electronics.