The truth is, the whole gambling is a game of speculation. Whether you’re a guru or not, losses are certain in the end. However, if you have the right skills and strategies applied into your games, losses will be minimized, thus giving you chances to win at times especially in skilled-based games. But at the end of the day, it’s not that luck or skills greatly matter, it’s the discipline and risk management that you put into gambling matter the most.
Losses are certain, no matter the level of gambling one has attained. I like to think that in addition to all those things you mentioned (skill, risk management, strategies), one still has to know when to size in big into high conviction bets. That's why gambling is not for the faith of heart. There has to be a confluence of many things before you can win.
luck matter greatly too. If you're lucky 99% of the time, you get to win your bets 99% of the time.