OK I’ll ask for the non wine connoisseurs here lurking, can anyone recommend a couple good Pinot Noirs and Cabs around $20-30 that would be good for a dinner party with friends? We usually do Josh Reserve or Decoy, something along those basic lines and everyone seems fine with it.
As you said, “Wine at this price point from Napa is almost always made in a tank, using wood chips and chemicals to give a desired flavor and color (often sweeter and more purple than unadulterated wine). That isn't inherently good or bad, but it isn't exactly wine, either.”
I love these challenges.
Decoy can be great; they're part of the Duckhorn empire, which recently sold to private equity, for whatever that's worth. Others on the pinot front that can usually be found broadly:
La Crema: some years these are actually excellent. Look for "Sonoma Coast" as the appellation
Sea Slopes by Fort Ross (this is Fort Ross Vineyard's "second wine")
Ken Wright from Oregon; generally speaking, Pinot from oregon costs less than pinot from CA.
For cabernet, that's tough. Not because it's harder to grow or make (it's not; yield per acre of pinot are generally MUCH less), but the market is the market... if I were really going to buy Cab on the cheap, I'd do a couple of things:
look for less known regions in CA (e.g., Silver Oak makes a cabernet in the Alexander Valley that is less than half the price of their Napa Valley wine) or Washington. I don't know those regions well enough to name a brand, but prices are lower. Chile has growing conditions very similar to Napa, for what that's worth.
Look to bordeaux. Most Bordeaux wine is at least in part Cabernet (wine from the left side of the river is typically majority cabernet). Terms like "Cru Bourgeois Superior" have at least SOME meaning, and wines of that grade can often be found in the range of $20-$40. It's a bit of an art and a science to understanding the various terms on bottles of wine from France, and each region has a different convention, which can make it a little confusing, I"ll grant you.
and then again, if I wanted what Cabernet is (a thick-skinned, bold red wine), but didn't want to pay a lot, I'd go back to Spain and the Southern Rhone.