Betting as an alternative income stream?

I have been in the army for about 3 months. It is very common for people to place bets for sports. Some of them treat it as an alternative income stream, some place bets for the fun and excitement of looking forward to something at the end of the day while some just follow their friends and place the same bets as them.

Well, to me, betting is a type of speculation. I believe no one can predict the exact outcome of a match based on statistics (let's not include match fixing and all those nonsense.)

Can one always win money through betting and use it as an alternative income stream?

So what do you think?