Every activity requires uncertain amount of time to become successful. Forex trading is much more difficult than any othr activity and you should always learning and practicing to become successful here. I suppose that traders, expecially novices, would better concentrate on their trading activity rather than think of success. Of course it's useful tovisualize your future in trading, however it's required to be attentive for details. You set a goal and then you should step by step reach it without second thought. There is no time for distraction.
It depends on what is meant by giving time to forex. Surely, if you want to achieve success, you need to devote much time to the activity which you want to master. Speaking about trading, there are so many things to learn there that it may take infinity to master every aspect of it. But it doesn't imply the idea that you should spend 12 hours a day before the computer screen and watch the price moves up and down. Only scalpers do that. You may spend time making analyses and making decisions and planning. Surely it requires certain level of concentration and involvement but it doesn't oblige you to restrain from drinking and eating and sleeping so that you will not miss the opportunity.
Trading forex doesn't really differ from any other activity: in order to succeed you've got to devote much time and energy to it. Forex is not an axception, the more you learn and practise, the better results you get. All the people are different that is why people need different amount of time in order to understand the market and start making ptofits.