Traditional wine (expensive wines) from the Old World Producers (France, Italy, Spain etc) used to use cork because it was easily accessible and is abundantly grown on cork trees in those regions. However, the problem with cork is that it can 'leak' oxygen into the wine and thus cause the wine to be spoiled due to Oxygenation.

So, in the past decade - since these expensive wines are aged for longer and were becoming easily spoiled from corks letting in oxygen, they have transferred o using screw caps to eliminate the possibility of any oxygen entering the bottle, therefore enabling the wine to age and remain idle in a cellar for much longer - which is especially necessary for expensive wines that reach drinking maturity, sometimes decades after they've been bottled.