It is tossed out on these (and other forums alot).... there isn't much hard data behind it though.
Statistics aside, I think it can be mutually agreed upon that the top priority for any successful manufacturer is to make money. And how does one make money? By selling products and services at reasonable intervals. It doesn't take a degree in statistics to figure that out. Apple business model doesn't benefit when someone buys a piece of internal expansion hardware from a 3rd-party vendor to upgrade their 2-3 year old computer. They make money when they sell you a new computer.
Correlation isn't as important as being statistically relevant. The average Mac laptop owner is not churning laptops on a 2/year burn rate.
The other factor being swept under the rug here is what is driving the relatively high churn rate. At an average price of $1,600 if this is an external chase of a MBP 15" that is the closer equivalent of the Mac Pro ... again that isn't even close to being representative.
Far more average laptop users are trying to get laptop utility out of their Mac laptop. With Applecare, probably closer to using them until the warranty coverage runs out. If depreciating them for business... it probably is not on a 2 year schedule. Those two are far more likely to cover a large group of laptop buyers than the corner case above.
You also used an average here to extrapolate a response that agrees more with your argument. Not every MBP I've owned has been a high-spec 15" model. My dead 2008 (pre-unibody) MBP was a $2,600 machine as spec'd and the other $2,400 was comprised of a pair no-frills 13" models, one new and one refurbished. These days, I use laptops purely for business and web browsing, while the MP tower is only fired up for editing gigs.
I purely made this example to point out that buttoned-up systems are generally more disposable than boxes with slots. And the nMP is a buttoned-up system that likely won't offer much internal upgrade potential outside of RAM and maybe a PCI-E SSD upgrade from a third-party vendor like OWC. As for the CPUs, I don't think any of us know yet (or do we?) whether the CPUs are soldered or socketed. Will anyone step up to the plate to make 3rd-party GPU upgrades for the nMP? Doubtful. The way this system appears put together, those items fall into the voided warranty zone.
More than anything, I just fail to see why you would argue these points just for the sake of arguing. The way the nMP is designed, you clearly need to buy a new computer if its major components no longer suit your requirements - and it's tough not to think that Apple designed it this way on purpose. There's more money to be made in selling in a new machine than allowing open reign to any enthusiast handy enough to swap out a GPU or add an expansion card (neither of which likely came from them).
Limit serviceability or limit who does the servicing? Not the same thing.
The latter has about as much to do with limiting support (long term ) costs than guiding folks to upgrades.
Older systems cost more to support. (those yelping about how they don't haven't run anything like the scale of support that Apple runs. The larger the customer base, the larger number of "cost shifting" customers going to have who will actively try to dump costs onto you. ) Frankly, with Apple's new model of "free" OS and App upgrades even more so. If folks with older system actually paid for the service that would be one thing. They don't. Apple could go into the "extended service" support business. They avoid it.
What I meant by serviceability is
user serviceability (sorry for the lack of distinction), as in upgrades and major component replacement - both of which I believe are of paramount importance to any computer being marketed as a professional workstation. These concepts no longer fit Apple's mold. I think what happened here with the nMP is that Apple said to themselves, "Okay, FCP X has been out for a while now. Let's build a machine tailored to running it quickly, while maintaining the 'less is more' aesthetic and disposability that is present in everything else we currently build."
I don't believe that I ever argued that older systems don't cost more to support because clearly, they do.
"Flop" really depends upon how low Apple set the bar and still be a sustainable Mac product.
There are two sides to the system here. One is Apple. The other is customers. If there is a growing number of customers heading to the same zone that the Mac Pro they could heavily tweak the design. The current iMac is quite different from the first 2-3 generations. Some of the basic overall goals are the same but the available technologies and users are in a far different place now. AppleTV doesn't have a HDD like it originally had and yet has grown.
If HP , Dell , and Lenovo each started selling 2-3 million workstation per year, Apple probably would jump in with another Mac closer to those form factors. At present, they collectively aren't even doing even half of that. If Mac Pro numbers have been in the 50-60K per year range then it isn't a huge hurdle (relative to other Mac products) that this nMP has to get over.
Most of the "flop" declarations are of the form of "If they don't sell it to me" or "if it doesn't put money in my pocket because my services/parts business depends upon dropped feature X" then it will flop.
I agree...mostly. Workstations are a niche market. They always have been, but even more so now because consumer-level hardware has achieved a level of performance that is acceptable to a wider range of consumers. Hence, many "prosumers" are no longer splurging for workstations. Why would they? They don't need them anymore. Again, as I mentioned earlier in this post, I firmly believe the only reason the nMP even exists come December is because of FCP X. If Apple didn't have development dollars tied into it, they probably would have pulled the plug on workstations over two years ago when they completely stopped caring about legacy FCP.
I don't think the nMP will flop on the account of the minority of pros and enthusiasts that are appalled by its lack of internal expansion. If anything, the nMP's success will be totally dependent on the success of FCP X. If FCP X fails to produce the market penetration Apple wants it to have, so will the nMP.