We are discussing a theory of value as it relates to labor. You asked for an objective measure of value. I am giving you one.
It seems the theory remains afloat.
Objectively the table is worth 50 lbs of coffee.
If it is your desire to bring money into the equation at this point we can easily do so.
Whose labor are we talking about, here?
If Peg Leg the Hobbling Pirate can only manage to harvest 20 lbs of coffee in the same time that it takes to build the table, is the table then only worth 20 lbs? What if the table maker is afflicted with narcolepsy and arthritis, and it takes him three times as long as previously stated to make the same table? Is that same table then worth 150 lbs of coffee?
Better yet, what if we're not talking coffee at all. What if we're talking wild berries.
Say we have Ted. Ted, over the years, has used much of his spare income to build a workshop attached to his home. He has built, bought, and otherwised compiled the machinery necessary to build furniture as efficiently as any one man might.
Then we have Chuck. Chuck picks wild berries on public land. He does this with only his hands and a small wicker basket.
In his workshop, Ted is able to make a table in 5 hours that would take someone without Ted's workshop facilities 20 hours to make. Since he makes it in 5 hours, is the "intrinsic value" of this table, in your mind, still worth only whatever amount of wild berries Chuck could harvest in 5 hours?
And this doesn't even account for the fact that building furniture properly isn't simple work. Proper carpentry is a skill earned through thousands of hours of experience. Any asshole with 2 hands can pick berries and drop 'em in a basket.
If we're only going to factor in labor time, what incentive is there to learn a skilled profession and go to the trouble of acquiring the tools for a dedicated trade? If I can get paid the same for mopping as I can for heart surgery, why the **** would I go study anatomy for 7 years? That shit ain't fun.
Essentially, your economic theory is AWESOME! Just not for any society that's more advanced than nomadic hunter-gatherers.