As noted in Xander's ♦ answer, it is a cultural reason as to why both France and Italy have such a lower beer consumption than their neighbors?
The answer would be all too simple to say it is because they can.
Not only is it a cultural thing, it may have an historical cultural reason. The top wine producing countries are Italy, France followed by Spain. The reason why Spain produces less wine and beer may be due to its' drier climate.
Spain produces about 5 billion bottles of wine annually and is actually home to the largest number of vineyards of any European country. However, its vineyards are more spread out and produce smaller yields than vineyards in France or Italy due to the drier soil common in many wine-growing regions of Spain. Although more than 400 varieties of grapes are grown in Spain, just 20 of those account for nearly 90% of all Spanish wine production. - The 4 Countries that Produce the Most Wine
Why Italy and France produces less beer and yet more wine may be due to the influence of its' Catholic heritage. Both France and Italy have strong roots with Catholicism and the Holy See. Italy was once the home of the Papal States (8th century - 1870) and France was home the papacy during the Western Schism. We must keep in mind that for Catholics wine is absolutely necessary for their liturgy.
In fact the Vatican is at the top of the list of wine drinking nations.
Vatican City is at the very top of the wine-drinking league with an average resident consuming an impressive 54.26 liters a year. Although it may seem surprising that the Holy See grabs top spot, it does have a uniform and unusual demographic. Its residents are older and tend to eat together in large groups while the consumption of Communion wine is standard practice for a large proportion of them. Andorra, another small European nation, is in second place with 46.26 liters consumed per capita. France places fifth, with residents drinking 42.5 liters of wine each year.
The World's Biggest Wine Drinkers
Wine Consumed Per Person in 2012