Did quark become susceptible to ASICs? It seemed like a solid algorithm. Were there technical issues, or did the coins themselves just never generate support due to lack of continuing development?
Bunch of coins use Quark as a hashing algo and yes, there are ASIC available for it.
How much alteration to the algo would be necessary to make it ASIC resistant again? Would it require a rebuild from the ground up?
you need to change the rounds and make it slightly different, but without turning it into something else like keccak, or you can change the parameters like in the new lyra for zcoin? but at that point i would change the name to avoid confusion andit would be a botnetcoin, and this is bad like asic or worst