WPGens came out as a product from a "plugin a month" challenge. The goal was to publish one plugin each month for 12 months. Each plugin was coded following best practices and WordPress standards. Also each plugin is very light, does not load unneeded stuff, nor does it make extra queries that would affect your site speed. After 4 plugins, and 5000+ active installations, support was getting more time consuming so i had to take a break from publishing free plugins on wp.org repo untill i form a team.
Thats where idea for premium plugins came out, as a sustainable way to continue publishing free plugins on WP repo.