Actually Dish Network "did" have a "somewhat" A La Carte system in place for about 4-5 years, with it ending last year around this time.
It was called the Dish NOW! prepaid system. With it you got access to all the Dish English/Spanish package levels(Dish Family/AT100/AT200/AT250/etc...), plus the premiuim movie channels were made available. It came with a Dish 500/DP301 SD receiver(or similiar). No VOD/PPV/HD/locals/Superstations were made available under this package.
But the SWEET thing about it was, you could order programming, BY THE DAY. And, if you just wanted HBO for a day or two, you DID NOT have to have pre-qualified programming(AT packs) in order to get it. So it came to like .53 cents/day for that 1 day of HBO.
But, of course, will all things this good, it got abused by people(I remember the big thing had to do with hotels/motels abusing it somehow, but can't remember the exact circumstances), and then Dish did away with it and replaced with the similiar, but IMHO TERRIBLE, FlexTV setup for prepaid customers.
Sure, now you can get any receiver you want, all the PPV/VOD you could want, locals, etc..., but now it all is based on 1 MONTH of prepaid service, plus they hit you with all the fees/restart fee($5.00 which is not bad), that go with a regular Dish account, which IMHO really destroyed the beauty of the old setup.
I knew it was too good to last, but I do miss having the ability, and NO OTHER SERVICE to my knowledge has even come close to approaching this type of pay TV setup, to choose what I want, and when/for how long I want it.
It was as close to A la carte(not TRUE A la carte, but close) as one could get, and it is dead. So I guess, in a way, Dish(and they are alone on this) already tried it, got screwed over, and said, "F THIS", and went in another direction.
But I do miss it.