Is this Drop7 game 'recoverable'?
Solution 1:
No, there's no way out of that situation that won't result in the end game.
You can drop the 6 on either of the 7's. That will trigger the 7, that will drop and trigger the 6 and then trigger the 3's.
Unfortunately, that will leave you with all the 2's and 1's and no way out from there. You can trigger the lone 2 on the left, but the combination of 1's and 2's leaves everything underneath inaccessible to trigger. You will obviously have chances to get more points, but there will be no way to get completely out of that situation.