Solution (partially) published:
The prize has already been claimed. If you check
the block explorer, you'd notice the address of the puzzle is empty.
I sometimes wonder do people get it solved really? I mean I have seen 3 or 4 BTC and ETH puzzle on bitcointalk itself but when I open the thread, people are still talking about it as it hasn't solved yet.
I guess it's fair but not so fair at the same time to have a megathread for a specific puzzle, especially when it implies a big reward. Imagine you've been working on the puzzle for years and throwing your findings here and there, and some stranger seeing the thread for the first time ever is able to make use of all that to claim the prize you should've been paid at least partially for as well.
On the other hand, I'd imagine 3-4 BTC are going to be worth a ton of money within a decade or so. It's already worth a ton of money
now, compared to what it would've been in 2012-2013.