In these situations they sell their bullshit tokens for real money (or BTC/ETH), so they would have run away with the actual money or something within an order of magnitude, not some fantasy "market cap".
It sounds like they pulled the plug after as little as 2-3 months of supposed ~50% monthly increases. So the chance that the real money stolen is somewhere in the vicinity of 1/4 the apparent loss seems high.
Your figure of 1/10 to be conservative sounds sadly sensible.
Your figure of 1/10 to be conservative sounds sadly sensible.