Really? I've never seen Twighlight Zone or The Prisoner included in a list of unreleasable Blu-Ray shows. If anything they are the shows that people said COULD be released on Blu-Ray. The shows that are nearly unreleasable in HD are the shows from the 80s-00s. Those are the shows that were worked on in video and have no hope of higher resolution without reverting to the originally shot negatives and re-editing the entire episode.
I've seen both. I also saw Trek TOS listed as unreleasable unless they farted around with the SFX which they did for TOS/R. And that show well predated the whole edit-on-video thing (and of course TOS ended up on Blu-Ray in its more-or-less original state, too). Anyway, the point remains moot so long as Blu-Ray remains backwards compatible with DVD. They're going to have to figure out a workaround (that doesn't involve remaking everything) by the time either Blu-Ray standards change and backwards compatibility is no longer allowed (sort of like what happened with PlayStation when they moved up the models, and also things like the move to Intel Core Duo Macs making it impossible to use most software from OS9 and earlier), or a new format comes along that is only HD (or, worse, only 3-D) compatible. They must come up with something, otherwise they're going to lose billions of dollars investment as 60 years worth of TV production becomes "lost culture".
As I say, the key remains whether or not the shot-on-video TZ episodes will be included in the Blu-Ray edition. If that happens, then IMO it opens the door for a lot of video-related material to be released in high-def, from old-school Doctor Who to All in the Family ...
Well BBC is already releasing The Next Doctor on Blu Ray even though it was not filmed in HD. But they're only releasing it so they can release a complete set on Blu Ray. I suspect something similar will be done with TZ. They'll upscale the couple video episodes to keep the set complete, but they will look no better than what your TV/DVD/BR player would do with the DVD version.
But it will still say nothing about what other old shows are released in Blu Ray. You could upscale TNG for example and release a Blu Ray set. But the image would look no different than what you get from your DVD now. The only shows that will see the effort to convert are shows where you will be able to see a difference. That's also why converting shows is not a moot point right now. If a show can be redone and released in higher quality I want to see it now, I don't care about a debate on format support and if my Blu Ray player will support the old DVD version.