This is why we see all these Early Access games that run like garbage. They are still in the develop new features and fix bugs phase, and have not yet gotten to the optimization/strip out debug code phase.
Early access game devs pushing unoptimized releases should set up their release system betterer.
Backfilling existing code with ifdefs and dealing with compile breaks and other more weird things can be intimidating, time consuming, with hard to define ROI, so I can empathize if someone doesn't do it.