There's a combination of factors but I would like to point out that Hard Cider is by far the fastest growing alcohol type today in 2017.

That said apples were brought by literally the first settlers to the USA. In the USA fruit growing ran into a problem of high maintenance. In England large-scale deforestation was already taking place and you could afford to have large free standing orchards. Meanwhile in 1600s United States you would need to fence off and protect your orchard because forests and forest animals like bears, skunks, racoons, etc still lived in abundance and don't understand that orchards are to be avoided.

In the south apple growing ran into two problems. 1st cash crops quickly became the most profitable and 2nd apples don't do well with the temperature and humidity extremes. In the north though by 1775 many small farmers had their own small orchard to make homemade cider with. John Adams and Thomas Jefferson didn't agree on much but they both loved cider as they reference its production and consumption in their letters to their wives. The majority of apple growing states though are in the great lakes area, the north east, and the Pacific coast. So for the first 100 Years of American history most modern apple producing places were being colonized and low in population. That said cider was still popular in the northeast because mollasses for rum had to be imported and grapes don't do so well in the New England winter but Apples are pretty frostproof.

And then cider was completely destroyed. The strongest places for Prohibition support were all in the Northeastern USA and many cider producing areas had fanatics and government agents shut down cider production or force them to switch to sweet non-alcohol cider. This was minor though compared to the wave of central European and Eastern European immigration. Those immigrants were used to grain being the main source of alcohol. Their large influx of population and the beer/vodka production they brought conquered the USA in the early 1900s. Before most immigrants had been from the English, Spanish, and French speaking world which have a colorful alcohol palette. Wine, Beer, Ale, Whiskey, Cider, Rum, and Gin were all in the mix so the USA's population had a big variety. When Polish German and Russian immigrants began arriving in huge numbers though they brought new techniques of beer/vodka production and this mixed with the boom of wheat farming in the great planes, and industrialization combined to create better and cheaper beer that could be canned and bottled faster than ever.

And that is pretty much where we are today. Cheap beer basically took over the USA from the 1920s until 1990s. Since then the craft beer movement, the explosion of wine, the increase of Rum/Vodka importation, and now the growth of cider is breaking the stranglehold of cheap mass produced beers in the USA...personally I'm still holding out for Mead to come back I love the stuff

Hope this isn't too off topic but why is always referred to as "hard" cider in the US? Was there ever a time when it was necessary to differentiate between "hard" and "soft" ciders?