Back Story, I am an old school D&D player from the 70s/80s and has been brought into D&DB by my grandson who wants me to DM some games for him, which also spawned and interest by my friends for a campaign.
I am also an IT guy who would love to see D&D moved a little farther forward on the tech side.
I purchased the master subscription for the sharing of the digital resources (mostly for the grandkid to have access <love that book sharing system by the way>).

I dove in and got to work on building a campaign.
So here i am with questions and complaints.

My complaint/question on this is: "Why is the home brew campaign building system not set up as a web based template format so that you would get a completed game like what you would get from a pay for campaign?"
There is an area to drop in DM notes Private and Public notes, add characters, share resources but no place to actually build the campaign and store it without going elsewhere to get a web area and build it ad-hoc. 
It would seem to me that the campaign builder should include a web area to create your campaigns connected to D&DB as part of the subscription and that area should be set up in template form, especially for the paid for Master Subscription.
(I would like to see the overview area, Introduction area, Chapters/parts of the campaign, Appendices and even credits as part of that template system.)

Being web based would also allow for direct pulls of the (as of now) Beta Encounter system into the home brew Campaign, giving them both more functionality and power.  

(I would see this as a possible means of revenue generation with being able to sell some of the digital homebrew campaigns, fully packaged and layed out prebuilt Campaigns, through D&DB that could be revenue shared with the people who create the campaigns?)

Am I expecting too much for a pen and paper game in a digital era?

There are a couple issues here, mostly related to what they're competing with.

First, there are already some pretty good campaign management websites out there. I don't use them, but I've poked around and they have some pretty nice features. It would take DDB quite a while to build out something that compares favorably to this.

The second issue is that Google Docs/Sheets exists. It does everything you need, it's free, and everyone in your party already has it and knows how to use it. There are plenty of other well-built generic organizers out there as well such as Evernote.

Third, I'm sure a non-trivial slice of the DM demographic still uses paper.

A fourth issue is that there's really very little need to connect campaign stuff to the nuts-and-bolts-of-the-encounter stuff. Really all you need is a link in your notes to the encounter (if that), and that can be done just as easily in Google Sheets as DDB would be able to provide in their own tool. The reality of this digital era is that you're going to have a browser tab with your notes and another tab with the encounter, and those both coming from the same source isn't going to make them any more close together or accessible then they already are.

I'm totally speculating here, but I would guess they have done the market research and at least some of what I said above contributed to a lackluster prediction in terms of revenue generation. I don't think adoption would be high - even if it's a better product, people are already comfortable with whatever tools they're already using. Hell, I took one look at the DDB encounter builder back when it released and haven't been back since. It's just not worth the effort to switch over when my needs are already met.

At any rate, for your own purposes I would check out some of the existing sites out there. The last one I looked at was World Anvil, which looked pretty cool. If demand proved high enough, WotC would be smart to just buy up one of these and slap their brand on it rather than try to reinvent the wheel.