Maybe I'm reading this wrong, but are there actually a lot of manga where the childhood friend actually has a chance recently? I haven't noticed. Please lead me to the promised land.
In romcom manga, it's a small trend that started a few years ago. Basically a few authors started to try to buck "the childhood friend is the love loser" trope. I don't think many lasted long, but it was a trend among new and independent authors for awhile. From there came a lot of childhood friend as the lead fighting the trope in some form, even one right now that is a harem series were they are all "Childhood Friends".
If you want another good example of the... I guess anti trope, there is the slightly more ecchi "Himegasaki Sakurako wa Kyoumo Fubin Kawaii!".
All in all, I can't think of any single one that got super popular off the top of my head, most just got a dozen to a few dozen chapters, but got published for probably "being different" and the editors probably thought there was a trend.