Yup. I believe you have the future of software sales in a nutshell there. Declines in retail sales for PC now and "consoles" in the future (whatever they will look like) will be a secular trend and will save developers and publishers a great deal of money.
I'm sorry that this is something that's leaving you out (and I weep with you that things like maps, notebooks, trinkets, and large manuals are a thing of the past), but it's how things are going.
I can agree with your sentiment, that the shift to an exclusively DD system is both inevitable and sad… But Alrik makes a good case, in some ways he sounds like my dad. My father is getting to the point where he's going to go "offline" and avoid the internet. It's not that he hates technology or the internet, heck he's an engineer and chemist… This may sound crazy, but what are the chances some people will reject the internet as it changes - as it becomes more and more commoditized or a vehicle for commoditization?
The above is a rhetorical… I actually wax and wane between gaming is dead/dying and it's going to be alright. As long as gaming has some enjoyment for me I'll stick around, but only with any frequency if there is a great bit of diversity. The trend towards genre coalescence all in the name a broader market will ultimately cannibalize the market they seek to tap - or at least it will because I will buy less.
Back to Alrik and DLC, another issue DLC fails to address is piracy… People will always steal/borrow/take the intangible, even at the expense of future enjoyment(IE if you like a specific industry or in this case game/genre you should contribute to it or compensate for what you take). DLC fails to address piracy because, by it's nature, it fails to add tangible value. IMHO, a good way to combat piracy is through adding tangible/physical value to the purchase - as you said, "maps, notebooks, trinkets, and large manuals" to name a few. I'm willing to pay more than 50-60USD for a compelling game with good extras(paper/cloth/leather map, meaty manual, perhaps a chance at receiving a random piece or article of concept art, ect).
Again, I have nothing against good DLC, in fact I like it when it is done right... I just think companies are being a little to narrow-minded, without a retail market option(which is fast becoming the case by requiring steamworks for retail purchases) we find ourselves in the same boat as with all other service providers(without physical value games are merely a service). How many people are happy with the monopolistic or collusive service providers in their life - phone, cable, internet, ect?