Contrary to the possible truth, long hair cannot be grown back once its shorn. For one, it becomes a huge task of patience. By the time you have cut your hair, you are comparatively conscious of the thing known as fashion. In which case, you do endeavour to look 'presentable' at most times. Thus, to have raggedly growing hair (which short hair does tends to be if untended) over a period of year/s (you do not get long hair overnight) is something that can try your patience.
Maintenance is another. Short hair. No matter how much you have to style it, you possibly dont have to spend as much on conditioners and hair clips as longer hair dudettes have to. To grow out your hair, you need to enter that cycle of 'when to wash hair', 'which conditioner to buy' and 'how to style it' a little more important, and a little more tedious to get into. Short hair - wash, dry, style. Which style is not necessary, because you can essentially follow only one. The price you pay for this convinience is a more ritualistic and regular trip to the hairdresser, which at the end of the day/ month is OK.
So, among a few things, short hair is easier to keep, and once you get that, its kind of difficult to get to have long hair. So, even though its physically possible to have long hair once youve cut it short, its almost a one-way process.
Unless you pamper your patience with hair weaving and stuff.