If a crypto-currency PoW is such that ASICs have an enormous advantage, then you're in a situation where just a tiny handful of companies with top-tier chip fab

If a crypto-currency PoW is such that ASICs have an enormous advantage, then you're in a situation where just a tiny handful of companies with top-tier chip fabs can control the currency by refusing outright to make the ASICs, or worse, only making them if those ASICs include specified features. For instance, you could only allow blocks to be mined if the block itself has a Intel - or US government - signature on it showing that it is approved by them. It's not uncommon for the supply of specialized hardware to be tightly controlled and regulated - just try buying a top-tier inertial guidance system with accuracy suitable for weapons use. Unfortunately the economics of ASIC manufacture is such that the entire world economy appears to be unable to support more than a small handful of top-tier chip fabrication facilities. Having said that, currently it's unknown if an "ASIC-hard" PoW algorithm is possible, or more concretely, how much we can narrow the gap between dedicated ASICs and off-the-shelf, or at least semi-custom, hardware.