Innovation Adoption
It is amazing to me that the responses in this thread largely ignore the original post, while inadvertently arguing its point.
The question raised was not whether you prefer Snow Leopard or Tiger or whether you think Apple is still innovative. It was whether OS X has run it's course on the innovation adoption curve and thus attracted a conservative customer base that finds innovation itself anathema. If that is the case, further innovation could actually hurt their bottom line.
OS X moved through the innovation adoption curve over a period of about five years. Innovators grabbed 10.0 when it was released in the spring of 2001. Early adopters were on board when their innovator friends told them that 10.1 was more stable and ready for prime time. The speed and feature improvements to Jaguar reached the early majority, and the late majority was on board for Panther. Laggards switched from OS9 (or Windows) to Tiger in 2006 or later. By then no one (statistically) was still using OS 9 - not even the laggards who at first didn't like OS X, but by now have forgotten that fact, and instead don't like the newest new thing. (I realize that you have your reasons, those of you who don't like Leopard or SL, but this is not personal, it's statistical).
Leopard is now entering the late majority phase, and the laggards are hanging on to Tiger until their PPC dies. Laggards that have switched will naturally grumble, especially if they installed Leopard on a G4. That's how the curve works, and it says nothing about Apple's inability to further innovate. Those same folks likely did not jump into 10.0 in March of 2001. That's ok. That's what early adopters are for.
There will always be people resistant to change. As long as there are enthusiastic innovators and early adopters it simply doesn't matter. If I don't like 10.9, but enough people love it to get the adoption ball rolling, that will be my tough luck.
Apple has a pretty successful pace for their adoption curve. Compare it to Microsoft. More than one in four Mac users is now running Snow Leopard; less than one in four is running Tiger or older. Nearly three out of four Windows users are still using XP or older, and the percentage of Windows 7 adoptions is still in the single digits. Apple is doing just fine with the adoption curve.
Here's the rub. If 10.7 is innovative enough to convince the early adopters, those folks will in turn convince the early majority. That's how it works. The OS will continue to get better, and the laggards will miss their favorite bit that fell by the wayside (remember when you missed the classic Apple menu? - yes even you, innovator, missed that at first!), but eventually they will find something to love in the newer OS, once it's not new anymore.
The good news for Apple - and for those of us who value innovation - is that the laggards only represent 16% of the market. What Apple (and anyone marketing anything really) is looking for is a fast blow through the curve. There needs to be something great in a new OS that makes innovators and early adopters jump in immediately, and that gets to the early majority phase relatively quickly. As demonstrated above, Apple is usually excellent at this. Innovators generally like Apple's offerings, as do most early adopters, and the majority follow happily in short order.
There are some users who miss Tiger, but the reviews of the early Leopard adopters showed that they absolutely loved Time Machine, Quicklook, Spaces, and Boot Camp/Parallels. And the majority followed. In less than two years, more than half of Mac users worldwide were running Leopard.
Early adopters of SL loved the rejuvenation of their three year old Macs, and thereby it's life extension. And once the early adopters are convinced, the majority follow and the presence of the laggards is just part of the model
Microsoft doesn't need as many adopters, because they will eventually sell their software to more than 90% of computer users bundled with a computer. Their slogan could almost be "You don't have to like us." Apple needs a successful adoption, because you need to love their software to justify buying their hardware, which is really the business they are in. That business has never been been better, and they have yet to drop the innovation vision. I wouldn't predict that they will do so anytime soon.