Given that, it doesn't help Apple to achieve the vision by supporting cable, satellite and optical disk formats of content delivery since these are all working against achieving the critical mass necessary for the vision to succeed.
If Apple came out with a variation of AppleTV with DVR capability and a blu-ray player, it would be the death nail to the vision... and Apple simply won't do it for that reason.
In the mean-time, don't look to Apple for a DVR or even an AppleTV with a blu-ray player, I believe that goes against everything they believe in.
VR, while I can appreciate your own point of view, I can easily counter these quoted argument snippets. It is simple chicken vs. egg. If Apple sticks to what they believe in (720p, buy it from itunes only, etc) they don't sell many

TVs. If they don't sell many

TVs, there isn't a lot of natural pressure on the content producers to do deals with Apple in support of the vision. Until

TV is dominating like iPods dominate music, the equivalent revolution cannot be realized.
Suppose then that Apple does something novel and actually reads the endless threads regarding

TV. There is enough product development nuggets in threads and critical reviews to effectively map out several next-generation

TV platforms. By building what mass market BUYERS want to buy, Apple can sell a lot more

TVs, which then strengthens their momentum toward the vision.
An

TV with DVR and/or Blue Ray doesn't kill the vision. Either and both will apparently give a whole lot more people reason to buy

TV. With deep penetration will come ever-greater leverage in working deals with content producers, making content pricing from iTunes much more appealing and getting much more desirable content into the iTunes store.
There would come a point where you just let the math fulfill the vision. For example, the monopolist cable companies pretty much raise rates every year. As iTunes content became cheaper, households would notice, eventually deciding they don't want cable anymore. Sure, this would give the DVR functionality a lot less to do, but there's a tangible step toward the vision.
Similarly, BD video right now is as good as it gets in mainstream video distribution. It's not fun to buy a "true HD"

HDTV and be limited to only iTunes handicapped 720p programming (at best) to show it off. Thus, cable/antenna feeds video (not on demand) that delivers a better quality picture now. And BD delivers a maximum quality picture for mainstream TV products.
The only legal way to get 1080p quality professional content on your new 1080p HD is BD (other than limited 1080p VOD options via cable/satt). So, someone who wants to watch their favorite movies at the maximum resolution of their HDTV is pretty much going to have to BUY a BD player; iTunes and

TV is NOT a solution at all for these people.
So, if they are going to spend that money anyway, build a BD option into a next gen

TV and that money can be spent on an Apple product (with a bunch of other great features) instead of a BD player. And by getting more penetration into living rooms, content producers will be increasingly enticed to make 1080i and even 1080p content available via iTunes (current US broadband bandwith issues set aside). As such content is added at attractive pricing, it will sell/be rented via iTunes.
Next-gen

TV owners will see they can then buy or rent BD equivalent movies via iTunes. They'll be able to choose whether they want to continue buying old technology (discs) or "vision" technology (itunes files). And again, with ever-growing penetration of

TV, Apple can negotiate better and better deals such that the latter could be meaningfully less expensive than buying the BD disc. Naturally, the public can get comfortable with buying the digital file instead of paying more for the BD disc, and demand for BD can fade away.
At that point, assuming both scenarios, the public would have a next-gen

TV that has a DVR function that might be completely- or mostly unused, and a BD player that might be completely- or mostly unused, but guess where we are then: the vision is realized.
- OR -
Apple sticks to its guns waiting for the world to decide that Apple's way is THE way to go,
-settling for handicapped 720p quality content at best for their 1080p HDTV sets,
-settling for paying a lot more for the mix of their favorite shows via iTunes vs. getting such shows- and substantially more programming availability- as part of their cable/satt bills,
-settling for the general lack of availability of some of their favorite shows & movies on iTunes
-pretty much caring less about the whole live event/live sports programming
-generally caring less about their local news/local programming
Now, how does Apple achieve the vision when it basically forces the market to make all these sacrifices now to do it the Apple way? Worse, not only would the public need to make these sacrifices now, but they would also have to PAY for Apples box so that they can embrace making these sacrifices. If Apple chooses to wait for the market to come around to the Apple vision- rather than taking tangible steps they most certainly can deliver to grease the wheels- I just can't envision them ever getting there.
A company casts a "vision" as something to aggressively go after and make happen. A company who casts a vision and then waits on it to magically come to them is only making a wish, and relying on hope.