> So what happened to Sears, IBM, RCA, GE, Kodak, etc.?

They never had a chance to expand in the post-computer era. GE was really close, but they switched to the "do everything" model a bit too early. Before computers, your only option was to have a financial stake in other companies, and this doesn't provide enough control.

As for IBM, I think it just lacks the ambition to do anything drastic. You don't get _automatic_ world takeover, you need to work for it. But others are giving a good run for it, just look at the recent acquisitions by Oracle.