These chardonnays should be consumed when young and fresh, from one to five years after bottling. On the West Coast, chardonnay drinkers consider the big, oaky California chardonnays as the benchmark. But California chardonnays generally don't age well and suffer from too much oak. If you sample one with an overpowering vanilla aroma, that's what caused it. Chardonnays made poorly smell like grapefruit-flavored candy or candied pineapple and often are sweeter than their French counterparts.
Winemakers love chardonnay for a variety of reasons.
It's a fairly neutral grape that can develop its flavors and aromas from the winemaking process or allow the terroir to come through. It has wide name recognition, leading to good sales. Winemakers know they can experiment with this wine to their hearts' content, developing a unique style. Some ferment the wine in stainless steel containers or neutral oak barrels, adding oak chips or oak staves to produce oak aromas and flavors. More than one winemaker has commented they don't really like to make a really oaky chardonnay in the California style, but that is what much of the public demands, so they do.