I'd actually argue that The Bloodline was the best thing WWE's done in a long long while, and certainly their most ambitious storyline ever. To have something like that last through so many years (not even counting hints of that back when Lesnar and Reigns were feuding around 2016 or so) hitting most of the time while only getting more and more over as time went on was an achievement.
But it wasn't all by design, though. Sami Zayn (and Kevin Owens as well) got way more over than they were initially expecting and gave them a ton of mileage, culminating in a big, big win over Gunther (who's also having a great, great run in WWE even if people are not too high on the Jey feud). Shit, I don't think they expected Jey Uso himself to become a main event player, but they ran along with it anyway.