Bar prices for drinks out of ratio with costs

One of the things that irritates me a lot is that nowadays if you are drinking in rounds - the price differentials between different drinks can be ridiculous. Yet if you buy the same drinks from a supermarket - there probably is little difference.

For instance: Why don't double spirits + mixer cost the same as a pint of beer? A litre bottle of smirnoff (about £10?) contains 28x35ml shots.. So a double mixer at cost is what? 71p. Plus a few pence for postmix coke or whatever (postmix costs virtually nothing) About the same price as a can of beer. (Most offers are 8 for £6 these days - so 75p a pint).

Yet in a bar - a double spirit + mixer often costs more than twice the price of a pint of beer?

The same applies with wine - a bottle of the sort of wine you might find in pubs costs about £4 (if your lucky) in supermarkets. You can easily get 3 'large' glasses out of that - or 4+change 'small' ones. So okay a glass of wine should maybe be marginally more expensive than a beer - but they aren't marginally more expensive - they are hella more expensive.

Is it just that beer drinkers like me are grumpy gits who won't stand for being ripped off whereas spirit drinkers like having their cash robbed from their wallets? Or is there something else at work.

It would be much better if all (non-speciality) drinks prices - e.g. basic wine, basic spirits, beer and cider - were sold at pretty much the same price. It would stop arguments between mates about rounds and make England a happier place.

And yes I am a tightfisted bitter drinker.