While Apple could probably be very successful with their current direction for quite some time, if the market changes under them the lack of Jobs might become more apparent.
It's utterly ridiculous to extrapolate from this, because so many other factors influence stock price and business performance - but it's more or less what you would expect of an organization supporting a brilliant leader, and is a tantalizingly similar data point with respect to Jobs presence.
Note that it wasn't entirely plain sailing after the return of Jobs. http://www.google.com/finance?chdnp=1&chdd=1&chds=1&...
This has surely been discussed endlessly elsewhere, but I think it's impossible for an autocrat to cultivate an autocratic successor - why would Jobs put up with another autocrat (and why would the autocratic successor put up with him?) I think this is a slightly different angle from the "cult of personality" aspect.