My CPU implementation produces on an i7-13700f the same performance as my GTX 1080 with JLP's code. CPUs are way more popular, and thus we can use many more computers if we focus on the CPUs and get better outcome.
Yes that's great and all, but the puzzles are getting harder.
Now that the previously considered "hard" puzzles like #64 have been solved, the difficulty of the next puzzle increases by a multiplication factor. This, I'm sure you already know.
I don't see anyone trying to attack #66 or #130 with the older GPU generations nowadays. Maybe it's because people are upgrading setups but it also must be understood that if you want to be able to crack the puzzle at the same rate as before, you will need more powerful hardware, otherwise it will take longer.
That's why they're mostly using 30xx and 40xx GPUs nowadays.
Your CPU may give you a good performance but you will need significantly more of them in order to get the same cracking time.
It helps that CPUs are getting cheaper but still you'd actually need to buy a new computer for each additional CPU unless there are multi-socket Xeons out there that people can benchmark and show similar performance to the 13700f.