That's certainly what it looks like. They told developers to "talk to us" if the change is a problem. I opened a support ticket immediately, but haven't yet heard back. I'm sure the people at ObDev have done the same.
macOS is a wasteland, if anyone is investing in it today then they are a fool or have been fooled.
The IPC performance is still abysmal (noticeable latency in several applications) after 16 years of kernel development. The scheduler is meh, the features offered by the kernel are generally meh. The UI and multimedia libraries were quite good, but they neutered them by incrementally removing customization opportunities, and now there's little left. No way to install a codec or container in Core Audio or Core Video, so you can't play or Quick Look Opus or VP9 or a Matroška file in standard applications. Their OpenGL drivers are garbage, absolute putrid garbage, especially on the integrated graphics; they still only support OpenGL 4.2 (read: the year 2011) on any GPU, and on Intel's GPUs performance is often 60% worse than performance on Linux and Windows (which are generally on par). If their Metal implementation shares its shader compiler with their Intel OpenGL implementation, then it's likely that you will never see any performance benefit from Metal on Intel graphics because your application is probably shader bound due to their drivers. And if we're being fully honest, if they were trying to make developer lives easier, they would add Vulkan support, but they refuse.