Now my question is; if gambling on single bet is that reliable why not many people becoming a millionaire or even resigned from gambling because they could have ended up accumulating the amount they wished to have in their possession.
I assume you are talking about sports betting's single bets and parlay. anyway, no one said that only doing single bets at a time will make you rich. the reason people "prefer" single bets is because it is a lot easier to win on that than doing parlay but just because it is easier to win on single bets does not mean you will be succesfull in it.