Do you know how the previous solver of puzzle 64 claimed his reward with just transaction fee of BTC 0.00063 while MARA isn't available yet and there also exists of bots out there back then?
Because most likely it wasn't worth it to set up bots since the reward was relatively small, so no one really cared.
Puzzle 66 can be cracked in less than 0.5 seconds (500 milliseconds) once the pubkey is revealed. One only needs a modest setup for that as well: a database of precomputed Tame DPs (less than a couple of GB, can be preloaded in RAM) and a low-budget GPU with a fast-returning execution kernel to find a couple of Wild DPs. Match with a Tame DP is basically instant. I don't understand people that setup multi-tens of GB stuff via BSGS to crack it in minutes, it makes no sense. Keep it simple.