In looking over these posts, various articles etc. it seems most are trying to make the Model S fit into a category to justify it's price.
The main gist of this part of the thread and threads like it in recent times has IMO been comparing the relative interior quality and features of Model S to other cars on the market, which finds them lacking when compared to a range of car classes and pricepoints. This isn't, thus, about trying to fit Model S into 70k or 100k category and saying it doesn't fit.
I guess the only category we are commonly fitting Model S into is one of a premium car, but even there some on this forum recently make comparisons to Volkswagen interiors and find Model S lacking compared to them... and I have myself compared Tesla's limited interior choices to those of Toyota.
While one could add all sorts of luxury gizmos and eleventy two way adjustable foot rests etc. all of that fluff can and does add weight which has the potential to reduce range and performance when you don't have a constantly churning ICE to drag it all along, and that wastes enough of it's fuel energy in waste heat alone to probably power a Model S down the road.
First of all, IMO this is an effort on your part (intentional or not) to make improved interior features sound pointless and heavy, which hardly many of the missing ones are. Indeed many are features Tesla used to ship themselves, but later discontinued, like ventilated seats. The real answer IMO is: Tesla is lacking in expertise and priorities when it comes to making a great interior.
If Model S buyers at large REALLY wanted luxury barges then why is the Model S spanking the S-Class, the 7-Series, Audi, Jaguar, Aston Martin, Porsche, etc. etc. They would have bought one of those instead of a Model S don't you think??
Because it is much cheaper and not really aimed at the luxury barge competition. As Elon Musk says himself, it is more of a 5 Series or 6 Series competitor anyway. And given its unique nature as a large-battery EV, it (together with Model X to lesser degree) is gaining buyers from a wide range of car segments (down and upstream), that otherwise would have gone for some other car size. We have people here who came up from a Prius, as well as people like me who came down from an Audi A8.
This is also why IMO Tesla could be wise to consider aiming at making Model S the Audi A6 / 5 Series priced and just moderately improve its interior (though priced options). There would be less work to get that done and probably more volume for them to be had around the 5 Series segment than trying to directly compete with 7 Series...
We should be asking "Model S owners why they bought them". Contained in their answers would be the reasons they thought the price was justified, and the criteria that defines the "class" the Model S occupies, or has created!
It is obvious to me that being the sole large-battery EV on the market is why many bought the Model S. Performance has been another reason. It also has a rather unique software system, another benefit. Some may like Model S's spartan interior design style (and IMO there is no need to change that to improve quality or features), but I'd wager most bought the Model S despite its interior, not because of it.
And once the main headlines gain competition, or indeed if Tesla wants people to continue buying Model S over Model 3, Tesla might be wise to address the interior question better.