On the contrary, I believed that altcoins will suffer because majority of altcoin traders will shift to bitcoin right now because its slowly making a significant growth specially those who are going to FOMO prior to SEC decision.

You should not underestimated them. They are very smart at his kind of situation. They are just waiting on the wings, delaying their actions until such time that the environment is ripe for the taking. But right now the money is on the bitcoin ecosystem so they are all swimming on that direction.