Hmm... not quite sure what you're disagreeing with... let alone
really disagreeing with!
First, xMac is not about
more "powerful" than iMac.
I think this is a good point to start to talk from.
What I see in both the xMac as well as the { cMP / tcMP / mMP } conversations is that much of what has customers riled up is the hardware's ability to be flexible to accommodate different use cases and priorities.
Thus, as a "starting point"...
Obviously wanting the more reasonably priced hardware as used in the iMac is priority one. Next there's lots of users (pro or not) who find the iMac screen a deal-breaker and want to choose their own screens.
These two lines are effectively talking about a very similar paradigm, namely that the definition of "reasonably priced" only applies if it is something of value to the customer. Thus, if one doesn't need to buy a new monitor, having one included isn't worth as much to that consumer than his twin brother who does need a new monitor. Similarly, a workflow which doesn't need the horsepower of dual GPUs sees the tcMP as having an "unneeded" extra expense.
And therein lies the crux and intersection of both the xMac and the 'modular': both are effectively identifying the paradigm that products which are extensively bundled with a high minimum buy-in cost are at risk of containing a significant "tax" consisting of hardware subsystems that they have to pay for which are not of particularly great value to them/their needs.
That's why the iMac is considered "bad": you're buying a screen regardless of if you need one or not.
Finally, probably the majority of xMac wish-listers want a standard PCIe slot for GPU (personally I'd be fine with just a high-end dGPU - I don't care about the upgradeability). Everything else is just details.
Similarly, some bought the cMP because of its empty drive bays was better suited to their workflows which called for future capability growth, or for increased local data storage .. which in the iMac or tcMP would have incurred a similar addition, but in the form of an { ugly / ungainly / unreliable } stack of external drives.
And this brings us back full circle to the Cube .. er, I mean the tcMac ... errr, the modular Mac:
Historically, both the Cube and Trash Can were marketed by Apple as 'modular', with those that needed more data storage expansion capabilities doing this externally, etc (FW400 & TB2 respectfully). However, both of these 'add an external drive' solutions have failed in the marketplace. But was their failure really due to the "spaghetti mess" of these cables, the higher cost of the peripherals ... or perhaps it was because the minimum starting cost for both were set too damn high because of things like nothing-less-than-dual-GPUs?
Finally, I suspect that there's still some ghosts of the Mac 7500/85/9500, where their degree of smart subsystem modularity did allow Apple to upgrade CPUs quickly, but they also had their product lines eaten alive from customers also able to upgrade (with aftermarket CPU daughtercards) rather than to buy new systems .. but was this then also not in part Apple's fault? I don't recall Apple actually selling Apple OEM upgrade CPU cards for their product lines - - and this points to a historical chronic weakness from Apple: once a product ships, Apple don't generally want to offer any hardware component upgrades for it to help their customers to extend their useful life.
