Even with doing a proper research, you can still have 10 losses in a times, but it also depends what kind of bets it are (single bets, parlay bets, ...). I don't bet that often anymore on sports, but I try to look for value bets. Sometimes you have good streaks that everything is going your way and other times not. Just keep track of everything that you bet and only at the end of the year, you should look at your return on investment.
Yeah, and that's right even doing proper research can't guarantee that you will not suffer from a long losing streak, if luck is not on your side you might suffer more even you have a knowledge regarding to the game, what I'm just referring to is the game that you are betting with, if you pick it randomly and you don't understand the game the chance of losing is high compared with the game that you know and the player/s that are playing is familiar with you, you can sort the advantages and you can decide according to your knowledge.
I do agree that there is no connection between making your research and getting to see what luck will do for you. I agree that people should be staying away from martingale type of methods just because of this, because that will not bring you any happiness at all, it will result with you eventually facing a big drop and there is no other way of making any profit at all, it will end with a losing streak and you will lose all your money after a series of losses.
However, I also do agree that if you know the game you are playing vs have no idea about the game you are playing, the losing possibility changes, you will lose in both, but when you do not know then you are going to lose a lot easier and a lot quicker without a doubt, that much is for sure true.