I can tell you that there are alot of well experienced gamblers today who view gambling, both online and offline, not as any means of entertainment but solely as a means for them to make money, this type of gamblers treat gambling as a serious business and this is how we usually see some of them that are particularly interested in playing lotto or pool, we see some of them sitting in the game shop, searching through a large paper which contains all the numbers that previously won, from this, they will try to forecast what number will play in the present and future, they can spend their entire day doing this.
But personally, I would say that the sooner a person realizes and only treat gambling as a fun venture, the better their life becomes, except if the person is already rich before he or she started gambling.
I will agree with you that there are still many gamblers who take gambling very seriously, sometimes they even consider it as a source of income and at the same time there are big gangs who are also involved in big criminal activities like match fixing.
And at the same time I will also say that just as these incidents are real, gambling in this way is definitely not a good sign. And I would also like to say that those types of gamblers often realize later in their lives that what they did was not responsible gambling, but rather that their lives are being put in a terrible situation because of that type of gambling. So we should all take risks responsibly before it's too late.