I have not posted before, so please bear with me. This is not intended to be a criticism of any individual.
Thatbags -- your statement is sort of correct.
All large companies, regardless of sector are ultimately controlled by their shareholders. Those shareholders are, in the main, only concerned about the return on their investment. They expect the companies they invest in to maximise their profits and continue to give them the maximum return on their investment.
Now the embarrassing bit. Many of those large investors are the pension companies that provide some (note, some) of us with our monthly income, and we expect the best from our pension companies. So indirectly, many of us are responsible for the profit orientated life we have.
I worked for a very large group of companies and if profits were down for two months in a row, heads would roll, and often redundancies would follow. Accountants rule.
With regard to the small outlets of larger companies like Tesco, Sainsbury etc. They are in competition with other shops in the area, not with large shops that may be a drive away.
In my locality I have a small Co-op and a small Tesco. Tesco, whilst they are dearer and do not stock the cheaper lines that their large stores offer, are very much cheaper than the nearby Co-op.
Small shops will always be more expensive as they have proportionately higher operating costs and are often open much longer hours (our Tesco is open 6-12) which their staffing costs are high.
Tesco will always be the primary target of criticism as they are the group with by far the largest number of small local stores. I suspect that the small "Sainsbury Local" stores (other stores are available) are also more expensive that their flagship stores.
So, Thatbags is correct, all companies will charge what the market will pay, not what a product costs to produce, and ultimately we are are all to blame to some degree or other.