In kpop, most of the time, there are members who are in the center that are mostly the most popular. However, in a well-rounded group, it is possible for all members to be equally publicly known.
The boy group from SM Entertainment SHINee, who debuted in 2008, is fairly an experienced boy group have members that are equally popular. Onew, Jonghyun, Key, Minho and Taemin all have big fan bases and they all are doing something when the group is not promoting.
Another example is Girl's Day. Though they aren't really equally popular, all of them are publicly known. All members had their time to shine. First, it was Minah when they just debuted. She was in many variety shows as the newcomer who does everything she's told to. Then, it was Sojin when their "Expectation" was released. She got tons of male and female fans because of it. She is also famous for being the oldest but still looking young.
Next was Yura, her time was almost at the same time as Sojin because of their sexy concepts. She became the talk of male dominated Korean sites. Then, she did some varieties like "We Got Married". Last but definitely not the least is Hyeri. Hyeri shot to fame after her aegyo on "Real Men" female version. It was followed by her lead role in the infamous "Reply" series. All of Girl's Day members are really popular in their own way and each has their respective fan bases.
Another group is Mamamoo. Mamamoo is a well rounded girl group. Each member caters to a different type of fan. Hwa Sa is mostly popular to the international fans because of her body. Solar is mostly popular to the Korean fans while Moon Byul is popular with both because of her boyish charms and Whee In is popular with everybody because she's cute. They also do different things like collaborations, appearances to variety shows and most especially, to Immortal Songs.
Other groups like Girl's Generation and 2pm are also kpop groups that have members that are all popular. Though when they debuted it wasn't like that, it changed gradually as the public got to know the members well enough.
I think it is because of the company as to why those groups have members that are all popular. They give each member their time to shine and they also give the members things to do that they know that particular member will do well.
Can you think of other groups that have members that are all popular?
