Sure, it's possible to remove a molly without tearing apart the drywall, but having lived in a house with chipboard walls, I've learned to appreciate them 
If I have 12mm drywall today and switch to 6mm chipboard/plywood + 6mm drywall. How can it be worse than what I have today?
If I have 12mm drywall today and switch to 6mm chipboard/plywood + 6mm drywall. How can it be worse than what I have today?
A molly in 13 mm drywall holds better than a screw in 6 mm plywood. 6 mm is not much to screw into, so for heavy items, you'll still need to secure them with molly.
Drill through the collar and push the rest into the wall. What remains is a 13 mm hole.
If they are small mollys, you can insert the screw a few threads, then push it in as far as it will go, i.e., push the molly back to the starting position, and then pull it out. But you can only manage this with smaller mollys (otherwise the drywall might give way). Drilling off the collar is also an option if you ensure it doesn't start spinning in the drywall.
Molly is all well and good, but I think back to the time when rawlnut existed.... rubber expanders for all types of materials, even in wet rooms... they were superb... wonder where they disappeared to...:O