The online art world is a double-edged sword: the Internet's vibrant culture of open, cooperative art-sharing also attracts non-consensual reuse and appropriation. Artists continually navigate supportive and challenging interactions on social platforms, including community-shifting disruptions; the reuse of creative work for training generative AI is only the latest such disruption. Research into creativity support tools (CSTs) often centers artifact-making, leaving the HCI community with few strategies to understand the downstream impacts CSTs can make on artifact-sharing. Seeking a framework that captures this, we develop the creativity supportive ecosystem through interviews with 20 online artists, and 8 data "stewards" with experience reusing creative data for training GenAI. We use the CSE to describe how creative communities perceive and respond to disruption, identifying opportunities to empower artists in their collective negotiations with disruptive technologies like GenAI: by centering artists as producers of value, identifying creative and alternative data practices, and empowering inter-community flexibility.