I would say that developer tools are a terrible market for that reason. Information products (screencasts, books, etc) can be extremely successful in the same market. Examples abound, including patio11's marketing training[1], egghead.io[2] for AngularJS training, Peepcode[3], Railscasts[4], and various other ebooks [5][6][7].

Most developers that I know have two common traits that make info products an easier sell. First, they're innately curious about their field. Second, they have access to a company credit card that will happily pay for training materials.

[1]: https://training.kalzumeus.com

[2]: http://egghead.io

[3]: https://peepcode.com

[4]: http://railscasts.com/pro

[5]: http://www.nathanbarry.com/authority

[6]: https://www.petekeen.net/mastering-modern-payments

[7]: http://www.jstorimer.com/products/working-with-ruby-threads