Simon Cowell tried to make more boybands after One Direction. All of the American majors also tried, launching new groups (Why Don't We, PRETTYMUCH, In Real Life) within a few months of each other in 2017. None took off, though WDW is still kicking around and was able to sell ~large theaters before the pandemic.
Why? The reality shows these groups often would launch off of faded. Cowell's X-Factor, where he made his '10s groups, is now cancelled, and he has lost his label to boot. And of course the TRL era on MTV is long gone. They recently tried to reboot it and it flopped quickly.
I also think most of the kids who would willingly be manufactured into a pop group are now trying to be online influencers instead. Less work and way more control. Meanwhile K-pop has gotten so big globally that the financial rewards for being a top idol are huge. On top of that there's never been any real passion for pop groups at the western majors, they just want to quickly shovel something out to cover their demographic bases. Meanwhile K-pop is full of companies that basically do nothing but idol groups.
I don't know where the K-pop wave is going, but the smart money bet would be that it'll peak fairly soon like any other trend. However, I don't see it fading quickly. BTS is the big phenomenon group and ~1/2 of the market here but a lot of other groups, including a large handful of girl groups, have gotten their hooks in at this point and you can see how loyal the fandoms are. I see it becoming a steady niche like anime. You want pop groups in the 20s, you go to K-pop.
Does that mean the East going to take over the global music industry? No, although the story of the 20s will be many countries around the world steadily coming up to parity. But PSY's hit aside, Korean soloists aren't taking off alongside the groups in the west. We have plenty of our own and they perform in English and live here year-round. They get the details of our culture in a way that is extremely difficult for foreign artists. Plus half the output of east Asian countries is ballads which the US market is largely uninterested in (occasional Adele hit aside.) Idol groups have taken off because they found a niche open.