ASIC-resistance is a mirage. Application Specific Integrated Circuits (ASICs) are made to do one thing only and will always beat general purpose hardware.
"General purpose computational devices like CPUs, GPUs, and even DRAM all make substantial compromises to their true potential in order to be useful for general computation."
–David Vorick, "State of Cryptocurrency Mining"
As an "ASIC-resistant" cryptocurrency appreciates in value, eventually someone would find it economically viable to produce an ASIC. Given the high development cost and relatively lower increase in profitability, for an ASIC-resistant algorithm such a market would be even more likely to be dominated by a single producer.
Instead, consider the upsides of an ASIC-friendly hashing algorithm. ASICs beat general purpose hardware by magnitudes which quickly curbed botnets mining with CPU or GPU. As ASICs are the most efficient tools to turn power into security, similar dominance of all available hash rate to Bitcoin's security would take magnitudes more CPUs or GPUs at vastly worse energy efficiency. It's easier for manufacturers to enter the market, which opens production up to more competition. Since the hardware is network specific, miners cannot hop networks to pursue every tiny shift in relative profitability, resulting in a more stable hash rate. Due to the upfront cost of the hardware, miners are—quite literally—invested in the success of the network.
After over a decade, ASICs have caught up to state-of-the-art miniaturization. Product cycles have slowed down. This reduces the advantage of mining operators with close ties to manufacturers, as the longer lifespan of hardware allows it to spread further geographically. When machines run longer, the initial hardware investment is smaller compared to the on-going energy costs which favors locations with cheap electricity. While China does have relatively cheap electricity, there are various regions with stranded energy due to abundant hydro, solar, or geothermal sources all across the globe. While previously most hash rate was situated in China, the recent crackdown on the Bitcoin mining industry there has expedited an already existing downward trend. Hopefully a lot of the currently migrating hash rate will show up in numerous different locales.
Finally, a change of the hashing algorithm would necessarily require a hard fork. Given the doubtful benefits, such a hard fork would be extremely controversial.
