Work is still happening in the background, but I don’t want to put a date on DX12 yet. While it’s always nice to be able to tell players when to expect a feature, this is one of the low-level parts of EVE that needs special attention. I want to be upfront and say that it may even ship next year. When we deliver it, it must have tangible benefits to users and work with all our existing content.
Hilmar has touched on some of the work we are doing internally in a recent Twitch stream, and there is another tonight. In short: We’re working on some of the lowest level, core parts of EVE, with code that has largely remained untouched for a very long time. This includes compilation of the client, window management, the networking stack and rendering. We want to ensure that we have a solid foundation for EVE going into the 3rd decade, and DX12 is certainly going to be part of that at some point.
It’s also true that we do have DX12 builds internally, but it’s important to emphasise that these are development builds…and trust me: You don’t want to be playing on one of these development builds 
Your comments about Wine / Mac are on point. There are considerations there that we’re looking at right now.