The future is mechanical.

As I've said before, I am not a fan of the mechanical method of harvesting grapes; the vines get beat up, the rachis is left behind along with a lot of grapes/raisins (all of which could become inoculum for, e.g., Black Rot) and all that shaking gathers up anything else that may be hanging around in the canopy.  (I noticed that one of Napa County's pest-traps was a casualty of mechanical harvesting in my neighbour's vineyard - it was ripped into shreds.)  However, the local bird population is ecstatic. They probably cannot believe their good fortune in the discovery that someone prepared a giant fruit salad for their delectation.
Ultimately, with labour costs rising at a rate that is not sustainable, in the near-future the mechanical harvesting of grapes will be de rigueur in the vineyards of the Napa Valley. Rumour has it that, in one or two years from now, when TWWIAGE starts to replant certain blocks of their vineyard the vines will be trained harvester-friendly, i.e., bilateral cordons. Machines don't make demands.
On a happier note, I worked in the Cabernet Sauvignon vines for a little while this afternoon - checking for any second crop I may have missed, taming errant shoots and assessing the leaf-pulling situation.  And I took a grape sample to see how sugar accumulation is progressing.  Not bad, at 23 °Brix the fruit tastes lovely and sweet, the seeds are browning nicely and the crop seems to be of average size.  I'd better sharpen my picking knife.