All Government could though make new laws to stop them being manafactured though....When will the penny drop and they actually realize it will have to be that way.....?
It's not "plastic" per se that's the problem, but certain types and physical forms. The really bad ones for marine life are polythene bags, which resemble food to some animals; netting and rope for their entanglement hazard; and "micro-beads".
The last are microscopic plastic spheres used as abrasives and bulking media in products like cosmetics and toothpaste so end up flushed down the drain and if even treated effluent is discharged into the sea the beads become ingested by creatures like copepods. It does not poison them, simply obstructs their digestive systems - reduce the copepods and you reduce the food supply for other animals.
The rest just end up creating a mess, but that's the fault of people not caring, not the fault of the materials.
Yes, we certainly could move to repeat-use packing and containers, or plant-based materials provided the plants are properly cropped; but you still need fuel to make and transport them. I had noticed over the years, manufacturers of commercial equipment moving from using those polystyrene foam "maggots" as packing materials, to versions made from some sort of flour; or various shredded-paper forms. Similarly, the polystyrene foam blocks between items and cartons, were becoming cardboard constructions - some involving very ingenious origami!
Scrap cardboard and paper can be turned into new versions, to a point anyway. Scrap timber could be used, if only by shredding to make particle-board or more paper. It can be burnt as a power-generation fuel, though that's not as sustainable as it may seem because the calorific value of wood is far lower than that of fossil fuels: about half that of coal, I think, meaning twice the fuel tonnage for the same MW/hr output.
Glass is recoverable, as are all metals; but these materials do use a lot of fuel in their manufacture or recovery. Glass especially, is not as easy to re-melt as it may seem, though I don't know the details.
Some materials are just not recoverable. Concrete from demolition sites can be, and is, crushed to form hard-core and aggregate, and any reinforcing steel it contains is salvaged as scrap metal; but you cannot revert old concrete to new cement, sand and gravel; and making cement uses a great deal of fuel.
There will always be some attrition: for example, you could turn 1 000 000 tonnes of steel into many products from ships to food cans; but you won't get back 1 000 000t of useable steel because whilst most of those products might eventually be scrapped in the proper manner, there is always some loss.
In the end we all have to face the fact that we are a profligate society! I wonder how many who so virtuously rinse and "re-cycle" every last bean tin, blow it by replacing their portable' phone every time the makers produce a new model?