The problem was that Nokia was funding a lot of the development of Calligra with as much as 20 developers. Unfortunately development of Calligra dead when Nokia

The problem was that Nokia was funding a lot of the development of Calligra with as much as 20 developers. Unfortunately development of Calligra dead when Nokia lost control of their market. While Krita developers continued to develop Calligra for some time, they decided to part they way because they just didn't had the workforce to maintain krita and Calligra anymore. It's sad for Calligra but in the end it is a good thing for Krita. Development of Calligra didn't died completely but it's not the same anymore.