single digit market penetration since the 80's.
Spin that however you like.
I don't have to spin it. As I said, more Macs than ever are selling. Plus, Apple makes the lion share of revenue and profits in that market, as it does in every other market it enters.
And more commodities than tools are bought, so what? There is now great freedom and choice in a "post-PC world", unlike 30yrs ago, as to what kind of tools and reliability and TCO (including time to fiddle with maintenance) do people need/want, to meet the computing needs they find themselves doing on a regular basis, the jobs to be done:
Does a family just need a $400 PC that gets them by and collects dust most of the time, while each member of the family gets a premium tablet and/or smartphone for work, education, and entertainment? Or, does a freelancer go for a $1900 Mac laptop as a reliable workhorse for day-in day-out use? The former PC is a commodity, lending itself to impulse purchase; while the latter is a tool -- the purchase of which the user weighed out.
Also, Apple's userbase isn't going anywhere as was thought 15-20years ago, but is increasing -- and increasing in relation to PC OEMs by virtue of Apple products having longer useful life for their users (as with Apple's tablets and phones vs Android devices).
The PC market is fairly saturated, and it is relevant to realize that the mobile device market is already an order of magnitude larger than the PC market was ever destined to be -- sort of like one PC per household, vs one (or more) mobile device per person on the planet; like there are more smartphones than cars. MS missed out on mobile, tried to emulate Apple, and lost billions on Nokia. Likewise, Google with Motorola, etc. Now, both Google and MS are trying to get into the premium hardware markets (and will be in competition with their OEMs)...
Nevertheless, the Mac is becoming more relevant than ever -- MS and Google are putting their efforts into cloud services that are platform independent. The average company is becoming more cloud-based, and giving more choice to its employees about what PCs and devices they use; and solutions companies like IBM are making the Mac a large part of the services they offer.
The world has changed, and despite the Mac being "doomed" for 30 years, it is still here... in fact, it is the Mac that has adapted and is adapting to the changing world, while Windows arguably has not: it is now the commodity filler for commodity products, just as Android is for most of the world's mobile devices.