It at least has the virtualization framework now. There’s a product called Anka that plugs into Jenkins and lets you deploy macOS VM images as build agents on top of physical Apple hardware. While slower than containers, and limited to 2 VMs (?!?) you can have reproducible and sane build environments via VM images.
to install, use and run up to two (2) additional copies or instances of the Apple Software, or any prior macOS or OS X operating system software or subsequent release of the Apple Software, within virtual operating system environments on each Apple-branded computer you own or control that is already running the Apple Software, for purposes of: (a) software development; (b) testing during software development; (c) using macOS Server; or (d) personal, non-commercial use.
Apple just really doesn't care about you, and as a developer, you're just a sucker to extract money from.
Realistically you can run more than 2 VMs with some work[0], but legally companies that provide CI and other virtual solutions can't buy 1 mac then get a license to run 100 virtual macs.
(insert name of any corporation ... listed on any stock market) just really doesn't care about you, and as a developer, you're just a sucker to extract money from.
