Because "including Spain, France and Greece" is a rather lacking description for 30 European countries:
Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland
Perfect example... Germany universally has this deposit system for their shopping carts but bypassed the handling and inserting of a coin into the cart at the height of covid.
Since then I have barely seen any reversal there. People still return their carts although they don't need to get their coin back where the system is still disabled. Or they just conveniently forget to use the system and still bring their carts back without locking them there where the system is operational again.
The actual deposit was basically only needed for the learning phase. After this it just works automatically.