It's easy to see how wrong this was, but there's still a chance that OS X will help move Apple forward in some markets. I have no idea of circumstances regarding Steve's return. I doubt that Apple's employees begged him but I never asked. It occurs to me that Apple purchased neXt because they knew that Jobs was capable enough to beat them. Apple purchased neXt for a very hefty price.
All computers use roughly the same technology, with tradeoffs for price.
A greater difference is in software. Apple had the best software in some ways but there were things that it didn't do well. It could be that he wanted to save Apple. But then why did he sell his stock immediately. It's more likely that he wanted to have a good power base.