If your network relies on dedicated ASICs, you're not as prone to this sort of attacks -- assuming you're the largest coin relying on these ASICs.
If your network is ASIC resistant in the first place, you would not need to be worried about being prone to ASICs that have huge hash rates. Building a truly ASIC resistant blockchain has its merits because GPUs are more decentralized and easily accessible for regular people.
ASICs are machines driven by greed and deceit.
If your network is ASIC resistant you need to worry about being prone to GPU miners that have huge hash rates. If you are GPU mined like the majority of at least the minor alts you have a much larger pool of potential adversaries. That's the point I'm trying to make.
It is also worth noting that one tends to underestimate the scale of GPU mining operations. Those are commercial operations buying GPUs
wholesale. Mining has become an uphill battle for the hobbyist ever since it turned into an industry, no matter if we're talking about GPU or ASIC mining.
That being said, I'm fully with you that the large upside of GPUs is that they are easier acquired by regular people. I honestly wish that ASICs would also be as accessible.