The big concern is that those person hold a huge ammount of coins,now imagine he moves the funds and sell all.Now imagine him starting a new altcoin and improving it every 3 -6 months making the price go higger and higger till it kill bitcoin,this is possible he made bitcoin ,and he can make something similiar to it and well once again collect a large ammount of coins and pay with the money from sold bitcoins.On that time we would see bitcoin worthing something like 100 to 150 dollars or less.
he won't do that, he loves his precious bitcoin too much
why would he want to shoot his own foot?
once he starts moving his bitcoins lot of traders will get nervous 👍