The diamond with information you're hypothesizing would have been dug up and modified by that prehistoric civilization, only to be put back under ground. Otherwise, it wouldn't have been found in a diamond mine.
And would you trust (very) future civilizations to come across a small diamond and think: hey, I'm going to fire a laser through this thing in a particular sequence and interpret the outcome as UTF-8? I think anyone who wants their data saved for posterity would give that some thought and not leave it to chance.
It's trivial to include macro structures that invite investigation, and utf8 is irrelevant. It doesn't matter what encoding scheme you use. utf8 is fine. All that matters is that there is structure.
They're still doing B2B sales after, so unless they're only making those deals under stringent contract, maybe some company will pick up the market and retail them.
Curious if they're stopping it because writing your own blu rays is relatively rare, or if they're hoping to cripple the bootleg movie industry from using them. Given this is Sony, I'm partial to think the latter may be the case.
