There's so many rules in the bible

Don't covet, don't lie, cheat, steal, kill, and gossip. And some other things like don't view violence on TV, don't listen to heavy metal. Don't get drunk. Why is it that people will do the above behaviour if they will get ahead in life, like every sin they commit in a day is like the total amount of french fries they eat in a single sitting at McDonalds, yet they claim to be Christians? Does it mean that sinning is okay to get ahead in life, since some people are clearly way more well off than others? Some people get trust funds for their kids, others leave misery for their kids. Life isn't fair, and apparently doing dishonest things to level the playing field is morally reprehensible to real Christians but not fake Christians yet real Christians are abandoned by everyone because nobody wants to be around someone with actual morals? And real Christians have to have a worse life just because they're not pricks like everyone else?