@Tearsax but here is the thing... it's not that unusual though. It may seem like it's not a lot, but it does happen quite a lot... it only looks like it doesn't because of how many non-childhood friends there are... but think about it, from office ladies, neighbors, classmates, club mates, cousins, coworkers, camp, cest, randomly meeting at restaurant and etc... there is actually a variety of tropes used for the main girl...
And there are tons of manga where the childhood friend and the MC get together... it's not uncommon at all...
And being a childhood friend isn't a factor for the failure of romance, it's just a factor the failure has. Being a childhood friend is a separate factor from the loss... plus, there are more non-childhood friends losing than childhood friends...