For now there will be no coin that can replace bitcoin, because bitcoin is the first and most popular coin and much in interest, perhaps for a long time the bitcoin will remain its crypto king.
Bitcoins are incredible. All other crypto coins have amazing goodwill to but comparing these two different families, bitcoins took the lead. Now, if you talk about who is popular and why is making more impact on internarial market, I am damn sure bitcoins would be the winning side. They are placing in hearts of their users because of best profit ratios. Altcoins are good too but definitely there will be only one king around.