As a psychic myself, perhaps I can shed some light for you. I think people assume that if someone is psychic they can see everything all the time - this is not the case. Obviously I cannot speak for anyone else who is psychic, but for me, this is how it works.
A client comes to see me, I tune into their energy, and I pick up information that they perhaps don't have access to. Don't ask me how it works, because I don't know. I just know that for some reason, I can 'know' information about a person if I tune it and am willing to receive information. Also, if I look at a photo, I can often 'get' information about the person/persons in it, this also works when I hold an object.
There is a certain sense of responsibility involved in being able to access information about another person, so I only do it when asked specifically. I don't run around trying to 'read' people all day every day.
Also, psychic information comes in different forms, clairaudience (hearing), clairsentience (feeling), clairvoyant (seeing). I'm clairsentient and clairvoyant, so I feel and 'see' information. It's a gift that I try to use only for others highest good. We are all on journeys in this life to promote growth and learning, and if someone is destined to win the lottery as a way of teaching them the lessons they need to learn in this life they will. Would it be for my highest good to win the lottery? I don't believe that it would be.
Also, I think you'll find that most people that are psychics are strengthening their gifts by raising their vibration to be in tune with a force I like to call Universal Love... and using their gift to win the lottery is a selfish materialistic act that, I believe, would be counterproductive to spiritual growth. However, this is not to say that a psychic will not win the lottery if it would be for their highest good, I just don't believe they would need to use their gift to win, they would just buy a ticket like everybody else does!
And just because you don't win the lottery it doesn't mean you'll be living in a gypsy tent!! lol. I live in a very nice house in a nice suburb and am very happy with my life. :)