Not 100% sure but I think one of the other big mistakes Apple made was to go against Jobs and not lower the price of the then-new Macintosh to sell more macs because doing so would have hurt sales of the Apple II.
Plenty of companies are like that, just look at the way Microsoft has acted when it comes to things they could (or even should) be doing but aren't doing because said things might hurt their core Windows or Office products somehow.