So the XBOX ONE, PC, and 3DS/WIIU aren't competition.
They are competition just not considerable competition save for PC but PC has just about always been relevant.
The point is why would anyone care about different models of the same console being lumped together. I would like a breakdown, but that wouldn't change my perception that PS4 is still on par, so far, with NSW on weekly hardware sales.
Are you trying to say something about actual install base? Like 94m PS4s might be actually smaller cause some PS4 owners have both this or that SKU? Id counter with how many NSW owners have multiple in the household because kids and portability. When the Switch has new SKUs how many sales will go to households that already own one or more? How can we possibly break this down into knowable double dippers? Want an asterisk? I guess won't change most peoples opinions.
This is why we have hardware _and_ software. The software is the real story in terms of money potential. Of course software stats on this site are kinda neutered now.
I'm just wondering why, when tallying up PS4 sales and comparing them to Switch sales, the existence of alternate PS4 models is never considered.
It is considered. The consideration is that they are lumped together rather than uselessly splitting them apart. The total sales are higher by x amount, even taking trying to take into account sales going to owners of other SKUs.
What other considerations are you wanting discussed? You havn't really explained what you think the consideration should be. That the install base of the PS4 is not nearly as big as the hardware 'sales' number would have us expect it to be?
There are PS4s that were bought and have been sold to re-sellers already. Same with Switches. What about consideration for those?