You go with what works for you; those who watch almost every match in each season, some of them don't waste time in running research about previous matches again as they watch both team performance before either last season or just in a concluded match; they can make their prediction from there.
Some people are just like your friend; even after spending hours and days making your research on your game option, sometimes your prediction comes out wrong, while the next player who just spent a few minutes selecting random matches ends up winning. It's just all about luck sometimes, but the research just helps increase your chance of winning.
Making predictions from historical data can be misleading sometimes, a gambler can use the previous matches of both teams to analyze but the outcome of the match he's predicting can go in a different direction. Just like you said a gambler can spend several hours trying to analyze a game but the outcome might be totally different from what you predicted.
Luck plays a major role in gambling, sometimes analysis doesn't help at all. I took out an hour of my time today to book a game but the first game on the ticket ended up going sideways and that's the match between Galatasaray and dynamo kiev, research can be overrated sometimes but it's still important.
Yeah Making predictions from historical data can be misleading sometimes however that those not mean it is not important, when you are analyzing a game you don't just analyze in one area you analyze in all area and then put them together to come out with a good prediction, there are clubs that there historical data is very important and they always follow that, for example Manchester United and Chelsea no matter how inform one of the club among this two is in a season it will always be a difficult match for the inform team to win the other, using historical data has really worked for me in many games I have predicted and is still working till date, in prediction use all the data you can lay your hands on.
Yeah luck play a role in gambling but not the major role what plays the major role is analyzing, when you analyze very well and then predict, luck will come in when maybe the game is now trying to play other wise, you can put luck in front when predicting a game, if Liverpool was to play a match with Leicester City will you predict the game with luck mind set by saying Leicester City will win or with your analysis that Liverpool is more inform and has won stronger team than Leicester City and will surely win them, analyzing a game before predicting Plays in major role in your winning.