In addition to worrying about software, Apple had to worry about supply chain, inventory, logistics, etc. And, unlike the Compaqs and Dells of the world, Apple was not in the business of making commodity hardware.

In any case, I think Steve was too busy in those days being a micromanager for the Macintosh team to even think about running the company. Don't forget he spent a lot of time alienating the Apple ][ team, who was responsible for most of the company's revenue at the time.

Getting fired, running a relatively unsuccessful company (NeXT) and nurturing a company into massive success (Pixar) probably gave him more valuable experience than if he had somehow managed to stay at Apple in the first place. And for all we know, the world would have never had the opportunity to see Toy Story or the Incredibles. Clearly, I see Job's firing from Apple as a win for the world. ;)

Also keep in mind that while at NeXT, they switched from a hardware and software company to a software company (and so did Be, which was the other company Apple considered buying).