It was a great idea in theory, but it seems that it didn't pay off in practice. Microsoft and Team Dakota announced today that they have decided to cease operations on the DIY game development tool, Project Spark permanently.
Starting today, Project Spark will not be able to be downloaded from the Xbox Live Marketplace and all online operations for existing users will cease on December 8th, 2016. Thomas Gratz, the community manager for Project Spark had this to say in an official forum post announcing the news.
"This was an extremely difficult decision for our team that we do not take lightly. When "Project Spark" transitioned away from active development last fall, many of our team members moved to other projects within Microsoft Studios. While this means there have been no layoffs at Microsoft, it also means it’s simply no longer feasible to continue the behind-the-scenes work involved with keeping “Project Spark” up and running with meaningful updates and bug fixes, so we have come to this hard decision."
When Project Spark first launched, it sold assets via microtransations for users to place in their game worlds, but eventually Microsoft transition the game development tool to a free incubation engine. Given that some may have purchased the title at retail, Microsoft is offering a credit to those users' accounts if it was purchased after October 5th, 2015.
Source: [Official Project Spark Forums]