Asic resistance can't be truly achieved at all. This article is explaining how a new player in the production of new asic rig has already started to develop new asic mining for X16r algo.
https://medium.com/@hardman/x16r-asics-in-the-fictional-world-of-westeros-b28460bf0322Any blockchain that implements a new algo that can resist asic player will be working temporarily. It's not forever or can be truly achieved to block new asic that support new algo.
In this case, it's safe to say that ASIC resistance is just a myth. The same principle applies to decentralization. Most cryptocurrencies claim to be fully decentralized, where in fact, they have some certain level of centralization within them. The most popular consensus algorithm (known as PoW), is probably the most centralized one in existence today. It's no wonder why Bitcoin is still largely dominated by big players in the mining industry (like Bitmain) leaving small miners behind. In order to keep ASICs away, the only way is to constantly adapt the consensus algorithm every couple of months. Monero might be doing the right thing in this regard, although it's yet to be seen how nodes could keep up with new changes in consensus every 6 months.
As for Ravencoin, it's still resistant to ASICs because no company has developed specific hardware to mine it. Once ASICs start rolling in for X16R, then the dev team of Ravencoin would need to quickly adapt towards a new version of the algorithm. Given how challenging PoW can be, I believe that the best route to maintain equality would be the PoS approach. That's why Ethereum has been considering switching from PoW into PoS. While they are still certain issues such as "Nothing at Stake", PoS still provides the ability for anyone to earn rewards and start securing the Blockchain in a much easier way than PoW. Over time, we'll determine if PoS is viable after all or simply flawed. Just my opinion
