When Jobs first came back, he eliminated every product that put Apple in competition with itself. I feel like that motivation stuck around for a while, though I think it may have been gone even before Jobs’ passing.
I was not following Apple closely back then, but I heard, that when Steve Jobs came back, the whole product lineup was a mess with many directly competing offerings. The iPad and the MacBook are not such a direct competition. Also, before the iPhone was introduced, but the rumor mills were already running hot, many people doubted that Apple would make a phone which could cannibalize their cash-cow back then, the iPod. Well, they did, they actually placed it in direct competition, and we know how that ended up :).