In Germany: Big car manufacturers do have round-table sessions where they share research informations with each other. However, they do not co-ordinate pricing.
When you feel like car manufacturers release models with similar specs within a short time frame, this could be why.
Another common one that I hear is, "Why do all cars look the same?" The truth of it comes down to two general factors, safety and improving aerodynamics to improve fuel economy.
Here's another "insider's insight": The car industry is a tough business. The profit margin is not like selling bottled water, especially when you consider overheads in R&D and the regulation compliant measures they have to adhere to, to sell in the German/EU market. Cars sold in the US are cheaper to produce because they go through much, much less vigorous testing, but then they are loaded with stupid add-ons (screens behind each seat, more luxurious user interface, better speaker+subwoofer combos, etc)