People wanting to donate a feature or fix a bug with Subversion are increasingly going to be happy with a Docker-based quick start. Most F/OSS teams want tests too, and y'all are very strict there in that regard, and someone who can write tests for your test-base covering code for your codebase is most likely going to be super-OK with Docker. Where that incentivized groups is left with pause for thought is on the consumption of contributions and the schedule for seeing consequential releases.
Now, there's another group who want to image machines and shove in "latest released" Subversion. Their problem is downstream maintainers of operating systems for one, and the lack of comprehensive Svn-dev-team install instructions to overcome maintainer choices secondarily. Ubuntu's at 19.04 now, and it's shipping Svn 1.10. The Mac's homebrew is at 1.12 presently, but it is quite often months behind. This group is happy to build from source (if that is reliable) and would use any on-platform or cross-compilation script to target the machine/OS they're interested in. They may not care to edit source. They may even be happy to skip tests - they just want the binaries in situ. How much of the first group would not want to wait for releases, and instead deploy unreleased versions of Subversion? Meaning they've donated a patch, have some assurances that it is being accepted as it meets standards, but don't want to wait any longer before productionizing it to some level?