the imperfect perfect competitive market

Academically, we always begin to study market structures with the understanding of perfectly competitve market form propounded by E.H.Chamberlin. It is an extended version of pure competition (char 1,2,3).
Its characteristic features being:
1. Large number of buyers and sellers
2. Product Homogenity
3.Free entry and exit
4.Perfect mobility of factors of production
5. Perfect knowledge
6.No Transport cost
7.No Government Interferance
It is important to note that all the sellers sell their produce at uniform price under such market form.
Any layman without the slightest study of any market structure will say that such a model is a myth and can never exist. Sure!can never exist...but along with that i have severe doubt about intrinsic and assumed features itself. I doubt them to be controversial and contradictory to each other.
For eg. There are no transort costs incurred which states that the produce is made locally and ubiquitously. However, if i consider 'A' particular area (a village, a collection of villages) then there will not be large nmber of sellers and buyers because each seller will then sell a considerable and significant output and same for the buyer. To this one may say that, so what if no transportation costs are incurred..the entire production and consumption might be spread out..say a country, a large state..but then what about 'Perfect Knowledge'? This feature states that information is free and costless and that the consumers and producers know completely of the market structures. In this case, if the economic activities are spread out then perfect knowledge is not possible because there is always going to be ignorance in some part of the geographical area which producers might take to their benefit.
Perfect mobility implies that factors canbe transferred geographically and occupationally. That means, one can work in mining ore one day, be a teacher of language speaking shakespeare and milton on the other and and go to a battlefield on some another day. Perfect mobilty fails to consider sunk capital that is intrinsic to occupations specifically. For eg. a blast furnace cannot be used in a farm and a sycth and chisel will never work in a manufacturing factory.
Alright, assume that such markets are or might be merely for agricultural commodities. In that case too product homogenity can never be attained. A corn from one field will be variant in its significant feature from another.
Feature 7 mentions no governmental interference. But since time immemorial, a government be it a monarchy (most of ancient princely states), a democracy (in Greece and Rome) taxes have always been imposed. This itself is a major governmental interferance. Even a 'Police State' will have to collect taxes for its maintainence of treasury and to safeguard the kingdom. Also, if there is no regulatory body like governement (if we assume very naively that no govts would then be present), how is the price uniformity validated? To this one could say that since a seller sells a very miniscule amount of output, if he increases the price, he fears losing his consumers to another firm; but what if he reduces price?- here the question arises: an efficient firm whose cost conditions are low compared to those in the markets might strategically lower the price to entrench market space and try to increase his sales. I studied that when prices are reduced by firms their total revenue is on a decline in P.C. market structure but my question is cant it be a strategy?
With respect to Free entry and Exit, how come existing firms tolerate new entries in market (in super normal profit status) to share their economic and hard earned profits? Would they not stategize to keep them at bay wanting to enjoy a greater share of the market and make hay while the sun shines?
..some grave doubts and grim curiosities!