IGN wrote:A little more than two years after its original release, Crystal Dynamics is preparing to end active development on Marvel’s Avengers, a decision it says it “undertook in conjunction with our partners.”
According to a blog titled “Final Update on the Future of Marvel’s Avengers,” support will discontinue on September 30, after which digital purchases will no longer be available. All solo content will continue to be playable after support ends, and multiplayer will also remain available.
You can find the mention blog post here
source: https://www.ign.com/articles/marvels-avengers-development-ending-delisted