I totally agree with you when it comes to the luck ratio in gambling although I know that they are some games in gambling that totally depends on luck like the casino games on many gambling website's. Sportsbet however, I can concur that a little percentage of 5% when it comes to the knowledge of the sport is need but still it depends on luck too because most of the time your knowledge on the sport won't cut it to secure a win or a positive result in your prediction.
The luck was suitable one to the gambling for the specific game and not to all the game.So the gambling site is not purely based on the luck,it also depending on the tactics used by the gambler.The tactics itself need of the continuity,if the gambler was stop or keep some gap between each gambling means the tactics will be forget by the gambler.The gambler who had huge experience in the gambling will do the practice of gambling game tactics daily.So he may remember of the tactics to the gambling,if the gambler get money he should remember of the tactics to make money from the gambling site.My opinion is tactics also help the gambler to make some money in gambling site.