Say the production of candy bars is 30¢ constant,30¢ variable, leaving 40¢ surplus [I should have specified expanded reproduction + 'average' profit].
Then the manufacturer determines how many cranks are willing to overpay...
Now the manufacturer's competition sells them for $90---which the crank, who's getting low on cash, readily purchases.
Then the first candy-bar manufacturer responds by charging only $80.
And so on.
When will the price-war stop?
Where else can it stop?
It stops at the point where production costs leave NOTHING for profit.
No matter what ANY CUSTOMER thinks.
What does that tell you? According to you the candy bar still has 'value' because it has been given unto it by labor - according to those customers who would buy it at below costs but not above its exchange value is less than the sum of the exchange values of the inputs.
I'm not sure at all what you're trying to say.
But I'll take a guess...
Customers obviously would be more than happy to buy anything BELOW cost.
But the capitalist who does so (or makes a product lacking in use-value) will soon go bankrupt and leave the market to those who sell commodities (possessing a use-value) ABOVE their investment costs.
: Hence LTV says nothing consistent about why and how people value things in trade.
Marx's LTV is quite consistent---but it is also complicated. There are many qualifications and special catagories.
: Get serious.
If you actually READ Capital LIKE YOU SAID YOU DID, we wouldn't be having such pointless debates, Gee.