This is what you call psychological barrier. Investors, traders, and even casuals can't resist the temptation to sell their bitcoin right now and cash it out because the price is too high. That's why lately you will see wild swings and not actually getting to $6000. The price is retreating today, going to $5300 so that's about $700 now from $6000. But don't worry we will finally reach that again and can be sustain. Specially is only a few a week before Oct. 25 and as we get closer to that date, $6000 will be touch then.