The imperfection of perfect competition

The conditions for perfect competition seem impossible to achieve. 

• Many firms 
• This is in conflict with economy of scale. If their are too many firms, the economy of scale will never happen. In fact the best economy of scale happens when we have a monopoly.  What that means is that the prices are not lowest possible.
• Little barrier to entry 
• Many industries have big barriers to entry. Be it money, time, patents. Only handful of industries participate in natural resource extraction, because barrier to entry is very high. Phrama requires years of research. Telecommunications need huge investments in infrastructure. It is sort of illogical to try to get into a business which is not defensible.  
• Homogeneous products
• Marketing and advertising have only one function, create differentiation.  
• Complete Information 
• This is in conflict with "many firms". It is not possible to have complete information about infinite firms. This is also in conflict with division of labor. If everyone needs to know everything about what he needs from another, he might as well build it himself. 

Perfect competition looks like a myth which only exists in theoretical models, except may be for unskilled labor. There are many. No barrier to entry, by default everyone is an unskilled laborer. They have nothing to differentiate by definition and because the only information required is do they have functioning limbs, it is easy to see by inspection.