yes, especially when btc starts to pick up and rise to new heights (20k+)
everyone will start to put their money into btc again.. that has been the case many times before and alts suddenly dropped up to 50%

however i do believe , that the btc dominance might be over, people are realising there are other coins than bitcoin.. but always watch bitcoin and if it starts to go over ~15k , it might go on a bull run.. and then you can start put some profit from alts into btc... when btc hits 20k or 25k .. you can start put some of the btc into alts again..
i wouldnt sell all alts into btc though.. just a healthy portion.. maybe 10-30%