The money/time is assuming they haven't been through everything - various interviews suggest they've they've only looked where they knew they had to. They only made an extended MOAM because they had a rough cut to reference. Would they have looked without it?
From what I've read, it sounds as if their search for footage has been pretty exhaustive, which is why I said that more money wouldn't mean much in terms of extended episodes. The ones we are getting are a pleasant surprise.
The Twilight Zone
The biggest comparison for me would be Doctor Who, where we have commentaries on 95% of episodes, some 49 years old. Even odd deleted scenes from the 1970s. Often a new documentary per story. (and still WE find things missed to moan about) But on the other hand its taking 13 years to release 150 odd releases at £20 a pop. Mistakes still happen. I'm just glad they weren't released in boxsets.
is another good example; the recent Blu-Ray releases (for a fifty year old show!) have commentaries for practically every episode (and many of the episodes have multiple commentaries, in addition to other features).