TBH, I don't know. Cost of restoration would be one factor: the BBC really goes "above and beyond" with Doctor Who to restore the material to as close as possible to its original condition. I suspect a bigger factor is that the market for this stuff is a very small, niche market.

The BBC press release has now been postponed to the end of the week.

...which would still be awesome of course! But The Mirror's version of the story doesn't even make sense. Full analysis of these claims on my blog but some conclusions follow:

• Of the 106 missing episodes, no more than 75 are realistically recoverable from anywhere in Africa
• If by some miracle, all 75 of those episodes were to be found in the one place, that place would be Zambia.
• It's possible that the wild claims of 90 or more episodes recovered could be true, but only if the stash also included large numbers of episodes that the BBC already holds in its archives.
• The claim that these episodes come from Ethiopia and the claim that they include Troughton stories are incompatible. Pick one.
• If they do come from Ethiopia, they might complete seasons 1 and 2; Ethiopia was the last place on earth known to have transmitted these stories.

My guess -- a trove of Troughton material has turned up in Nigeria that includes a big chunk of season 5; some of which the BBC already has, much of which it doesn't. (But I still hope it's 75 missing episodes from Zambia...) ;)