In 2000 ez was trying to get into AMS, but was blocked.
I take it you mean as a base? I flew LTN-AMS with U2 (or EZ as iirc they still were then, never seen the logic of that change) in 1998.
I can see that this might be the final straw for Easyjet if their Madrid base is either unprofitable or only marginally profitable.
They have already announced a major cull at MAD - base is going, some routes operated from other bases will stay. I suspect they might hang around a little longer at BCN, as it has beaches nearby, unlike MAD.