as a non-Apple swift user this is disappointing to hear, but i recognize this as a legitimate explanation and i appreciate the honest response.
regarding the “implementation work” aspect: to say that contributing to the compiler is challenging right now would be an understatement. even for someone who has a C++ background (an uncommon skillset in this community) just compiling the compiler itself is not easy.
i checked the Getting started guide to see if anything has changed since the last time i tried, and it seems you still need to have 70 GB of free disk space. i get this does not sound like a lot if you are building on a corporate-provisioned cloudtop/device, but for the majority of the time (65%?) since i started using swift (in 2016 or so) i was unable to build the toolchain on my personal machine because i did not have 70 GB of free disk space, or time to clear up 70 GB of disk space to build a toolchain. and to have a serious workflow for contributing to the compiler, you probably want to sustain more than one toolchain build per machine at a time.
to use sccache in docker also requires manual installation, although thankfully i don’t see any references to distcc anymore.
aside: i’ve never tried to contribute to the swift corelibs, but it sounds like there are similar obstacles in that domain as well.
obviously, contributing to any open source code base is going to require some amount of effort from the contributor. but i don’t know of many open source projects that have as many barriers to development as the swift compiler does. healthy open source projects prioritize onboarding and invest effort in making the project an attractive pursuit for community members looking for something to do. in the absence of that, the list of developers with the determination to implement things in the compiler instead of complaining to Apple employees is going to be short. this should not be surprising either.