Yeah, there's a ton of money just sitting there for whoever makes a viable replacement for the 2012-2015 rMBP. Anything with windows on it is disqualified, and I don't have the inclination these days to deal with driver issues from running Linux on something unsupported.
The closest I've seen are the Dell XPS 13/15 and Thinkpad X1 Carbon/X1 Extreme, but I'm not a fan of the Dell build quality, and the linux support on the Lenovos isn't quite good enough yet (Nvidia Optimus driver issues mostly, and issues with battery life relating to it).
The other potential option is System76, but their laptop hardware just isn't up to par - their POP!_OS seems pretty good though, despite the horrible name, so they are part of the way there.
The closest I've seen are the Dell XPS 13/15 and Thinkpad X1 Carbon/X1 Extreme, but I'm not a fan of the Dell build quality, and the linux support on the Lenovos isn't quite good enough yet (Nvidia Optimus driver issues mostly, and issues with battery life relating to it).
The other potential option is System76, but their laptop hardware just isn't up to par - their POP!_OS seems pretty good though, despite the horrible name, so they are part of the way there.