One of the first things workers do is to remove weak shoots with fruit that won't ripen. At this point the skin color begins to change and the berries start to soften. Workers go through the vineyard and remove the green clusters that lag behind. The remaining fruit then develops more concentrated flavors. Some growers do all of this work, and others do little or none of it.
Some people are willing to get six tons of grapes per acre, while others want only three tons.
Another grower harvests fewer grapes, but charges more per ton. Of course, there are other factors that go into the price sticker. There is economy of scale, which allows large wineries to pay less for supplies such as bottles and corks. Marketing and market positioning also make a difference. And then there are the fabulously expensive wines.