Upto what limit can the plastic be used in Automobile sector?

As all of us know Plastic is one of the finest as well as worst invention ever made.It has all properties which are useful in creating todays modern gadgets and other things.A major impact was made by plastic especially in Automobile market and industry.Plastic has been commonly used because of its mouldability, strength and light weight.Todays automobile body works mainly depend on plastics as it helps in weight reduction of vehicles which helps in increased efficiency.Plastics have been used along with aluminium to produce a composite material of desired properties.As I know plastics were mainly used in dashboard, steering wheel, engine covers, gear handler and some moulded parts.But my question is whether this is the limit for use of plastics in automobile sector?
If plastics of high strengtg equal to aluminium or steel were found what are the advantages we could have?
If plastic panels of highstrength were used can it overcome collision?

Introduction to plastic:
plastics were made from by products of crude oil.The distillation of crude oil results in small mononers.These monomers were bought by companies and add them to make polymers.Plastics are of two types majorly hard and soft plsstics.They are synthetic and Plastics were made from polymers.So if crude oil production stops plastic raw material also decreases.
Please share what are the other parts in a vehicle to have used plastic.