Hear me out.
I do think they need less effort than female groups and soloists to grow a following, but It's still necessary to expand their fandom and elevating their popularity by a lot.
The thing is that when a K-pop fan thinks about a 'hit song', they think about Korea and It's general public only. But It's an outdated perception, from my point of view.
With the heights K-pop has reached globally, It comes to a point It's international niche/community is bigger than the demographic that consistently listen to K-pop in Korea. So, thanks to that wider reach, a lot of korean songs can be well known by a large audience outside Korea. Including boygroups songs.
I personally can't think of a boygroup that don't have one or more popular songs in any way and became somehow big.
When they don't do, even If they have a good fanbase, they will stagnate before becoming too big, as their reach will find a limit.