No. It’s a nice to have but not a must-have. Kpop has shifted its worldview with a constant international presence, so it all depends on the group and what it’s trying to achieve. Groups that have not been perceived to have a strong fanbase in Korea and have targeted more heavily internationally have had tremendous physical sales, touring revenue and/or streaming. Groups that focused on building the fanbase in Korea have also had tremendous physical sales, touring revenue and/or streaming. Similarly there are groups that focused solely on one market and had none of those.
I think someone said it best upthread - it depends on the group and what they’re trying to accomplish.