Some people have known bitcoin since some years ago but they are still struggling. They are struggling not because they did not have money in the past but just because they are trading. They wanted fast money and they lost and lost several times.
You got me a bit perplexed there because it seemed you yoked investment with trading. Both aren't the same thing. Knowing about Bitcoin and still struggling being successful with it as you posited may suggest knowing and then just investing only. That's not in any way the same as trading it.
Trading is only good for those that are not losing. If you have been trading for some months and losing, stop trading and be patient. When the price of bitcoin fall, you can buy it and hold it instead.
Trading is good only for those who've acquired the skills for it. It doesn't matter how long one has been trading or stays out. Without proper skills, one will still lose.