I would put the over/under on timeframe to being broken wide open at a week (maybe a month if the implementation is particularly novel).
Ok, now we're talkin. I did not know this, so very helpful answer. Probably best to try a different approach rather than try to get blood from a stone.
However, you are saying that it IS possible, just only for one week, so I have a pretty bizarre idea: Can the obfuscated software spawn a "child", a newly obfuscated copy that wakes up and generates a new keypair? The "adult" then sends the money it is guarding to its child, and dies.
Blocks would have to include some ID or something of the child, which the parent could even sign. After its ID is stamped into a block "Child" becomes the new "Adult".
If the user has access to the software and the software has the secret the user has (or will eventually gain) access to the secret. If that were not true the rate of software piracy would be approaching ~0% by now.
I was just assuming the developers leaked keys to their friends, or that people cut out the check-for-license part even if they couldn't fully read it.