27/09 - I'm talking engine design improvements that could have placed the 172 into current-level cutting-edge engine technology, with improved engine construction materials, engine design changes that could have improved fuel efficiency by 25-30%, airframe design changes that could have improved the drag coefficient, construction material changes that could have seen lighter weight with the same or more strength - along with numerous other areas where Cessna technology still lives in the 1950's.
In the same era that the 172 has been in production, we have seen automotive improvements that make the automotive products of today seem like space-age, as compared to the automotive offerings of 1957.
There's nothing like manufacturer inertia and resistance to change - or more importantly, resistance to the costs of changing production procedures from manufacturing equipment that was paid for by the mid-1960's, and which has produced a regular cash-cow ever since.
If the automotive manufacturers were still building motor vehicles on 1957 production lines and equipment, they wouldn't be able to sell anything, such would be the cost of manufacture and the inefficiency of the end product.
If the 172 had kept pace with automotive advances - today, it would be built entirely by robots, with faultless, 100% repetitive precision, contain large amounts of composites and alloys, and high-tech plastics and resins, be 30% more fuel efficient, have a considerably lower drag coefficient, and cost 2/3rds to buy new, of what it did in 1957.
Corporate manufacturing would still be building wood-and-wire biplanes, and wooden-wheeled drays for transport, if they were allowed carte blanche control over competition and technological advancement.