CHANGES WITNESSED OVER THE LAST FEW …

With time, manufacturers have looked into three aspects of packaging, viz. weight and thickness of the packaging material, the effect on the environment of the packaging material and the cost of packaging.
As transportation cost goes up, manufacturers are making the weight of packed material lower per unit, hence cardboard cartons are replacing wooden crates. One other reason is cardboard boxes are made from waste or recycled paper; on the other hand, trees have to be felled for making wooden crates.
Tetra packs are not breakable like glass, they are also an aseptic form of packaging that can store milk for longer periods of time without getting spoilt. Vending machines store plenty of milk, which can cater to a lot of people; installation of these machines has also removed the packaging cost altogether.
Plastic doors and windows are lighter and last long, unlike wooden ones which get spoilt due to sun and rain. Use of plastic for making doors and windows also does away with wanton felling of trees for wood.
Cardboard is made from recycled paper and extensive use of this material for packaging helps save use of other non bio-degradable material; compared to heavier material like wood or metal, cardboard is a lot lighter.
Pyramid packaging replacing square or rectangular shaped packaging helps in storing more packages in any given space.
Customers today are asked to pay the cost of plastic carry bags to dissuade them from using such bags which affect the environment as they are not bio-degradable. 
Earlier brown paper bags were used as packaging material. To make things attractive plastic bags were introduced. But, as civilisation became conscious of the ill effects of plastic, items like cloth was introduced for packaging or carrying material.
Advertisers use packaging very intelligently and aesthetically, so that the product attracts the attention of prospective customers over other products in the same category. The packaging material, the written words, the shape and size etc are all micromanaged at the time of launching a new product.