Roman's reign after Jey left made everyone look weaker, because Jey made Roman look weaker. Roman started burying himself earlier than we think.
Let's look at some events.
Roman essentially beats the Usos (near torture) to the point of acknowledgement. This established how violent and aggressive the group is (which is probably why WWE shit on the Hurt Business so bad). This is the foundation of the group.
Roman let Sami join the Bloodline. First mistake by Roman that leads to his leadership being questioned. The "outsider" Wiseman was already an issue to Jey, now another white dude is being invited? It took forever for Jey to accept Sami, but Solo never did, because he was true to the foundation. Solo couldn't wait to put hands on Sami.
While Jey is also turning face at this time, Sami's betrayal was also a bad look for Roman's leadership, since it proved Jey right all along. Sami was never right because the Bloodline is founded on the other members achknowging the alpha. How can Roman be the alpha if he can't even keep Sami in check? Sami's defiance was a constant fuse for the Usos (especially Jey) to eventually blow up against Roman, leading to Roman starting to take Ls in the ring.
Solo and Roman lose to Sami/KO.
Solo and Roman lose to the Usos, except this time Roman gets pinned by the very person who has always challenged his leadership.
Throughout the last year or so of Roman's reign as champion, Solo either interfered to keep Roman champion or took the L to keep Roman appearing strong. There were many times though that you could tell that Roman's leadership was side-eyed by Solo, especially when Roman showed mercy to people.
Bloodline leadership is like this: Roman was Caine, Solo is O-Dog.