"Modern wine screw caps are highly engineered pieces of packaging technology, developed over many years to do the job that corks seem to do only imperfectly. That job is quite simple: to keep the wine inside the bottle and to seal out the air. For a while, some tried to turn cork's deficient sealing capability into a strength, arguing that a slight amount of air exchange is necessary for aging. However, it is now generally agreed that wine is naturally bottled with enough air dissolved in the liquid to permit it to mellow with age. Even if that were not so, modern screw tops are so precise that the winemaker can adjust the tightness of the seal to allow more or less outside air to enter, without the risk of cork taint."
Screw Tops: Get Used to Them (washingtonpost.com)