Sadly, Cursor will always be hampered by maintaining it's own VSCode fork. Others in this niche are expanding rapidly and I, myself, have started transitioning to using Roo and Cline.
Cursor took the best course of action at the time by forking but needs to come back into the fold. If VSCode is restricting access to APIs to CoPilot, forking it publicly and putting that in the Readme, “We forked VSCode since they give preferential treatment to CoPilot” would get a lot of community support.