It’s stuck.If you remove the tweeter you may be able to push it out from behind. If not, get 2 flat head screwdrivers and wrap the ends with some electrical tape. Spray the ends of the screwdrivers with some silicone and gently work them in between the speaker and cabinet 2 to 3 inches apart from each other. If the drivers are stuck to the point of bending the speaker, try different spots.
If you know for sure the drivers will be replaced, another method would be to get a razor and cut around the outside edge of the cone. Then you should be able to get your hand inside the speaker and pull it out.
When the speaker goes back together, be sure to use new foam surrounds. I’m guessing they should be around $20 for a kit that does both speakers.