While I'm not completely convinced that the countermeasure of "spy mining" completely mitigates the attack, it does appear that this is not a new vulnerability. Further, if a pool had all of the hardware under one roof, it wouldn't be possible to spy at all which would reinstate all of the problems outlined in the paper.
I don't see how "spy mining" actually helps. It seems a bitter pill to suggest that now we need ANOTHER layer of validation on top of the existing protocol, further increasing Bitcoin's energy cost.
And if you believe this mitigates the attack, then "spy selfish miners" must also exist then, keeping parity.
Proof of work as implemented now is fatally flawed, and it's primarily a tenant of faith instead of logic that it isn't. Just google "selfish mining debate" and enjoy the plethora of inane and tedious reactions.
But also: yes the paper is not at all new. After replication and other checks, the Bitcoin community has gotten up on its high horse, plugged its ears tight with wax, and started signing, "I can't hear you!"
Personally I'm skeptical of all blockchain hype but as I have people in the industry close to me I try to keep an open mind and at least understand the technical and game theoretical aspects of the space. I can definitely agree that the aligned interests of those pressing for adoption and increasing prices has made rational debate difficult in many circles.
