The State of Developer Ecosystem in 2017 9 years ago
skewed towards Jetbrains' customers.
Doesn't seem so. From their methodology [1]:
"We used Twitter Ads, Google Adwords and JetBrains' own communication channels to invite potential survey respondents. To minimize possible bias, the reports include only responses coming from Twitter Ads and Google Adwords."
[1] https://www.jetbrains.com/research/devecosystem-2017/demogra...