You could very well be right. I really don't want to take away from the fantastic work that the WSL team has done.
However, as a developer, I want a development environment that is stable and easy to setup. Windows has always been a huge mess to develop on and is the red headed step child as far as support for every open source project out there and the WSL implementation solves 90% of associated problems.
That being said... both MacOS and Linux are easier to code on. From compiling C extensions to file path parsing, UNIX-based operating systems have just turned out to be better development platforms. From my perspective, at least.
To emphasize, I have less of a problem with the work-in-progress nature of the project as I do with the release cycle. If the operating system stands in the way of getting work done, then the end user shouldn't have to face the dichotomy of whether or not to sacrifice core system stability in order to achieve his or her goals.