If, at the end of the game, we reshuffle the discards but STILL don't have enough treasures to go around, what do we do?
I'd just follow the rules as they appear;
Rules page 6 wrote:
If there are still compass roses left while drawing the treasure cards, shuffle the discarded treasure cards and continue with the distribution as usual. After the distribution is complete, the game ends immediately.
The distribution includes discarded treasure cards. If they're all gone you distribute what's there and the game ends. There really isn't much more you could do anyway.