You're actually hitting on something real here. Oblivion's guilds are way more of a job board experience than Skyrim's - that's not a bug, it's kind of the design. The Fighter's Guild especially stays pretty transactional throughout. You're basically a merc taking contracts, and yeah, nobody's gonna pull you into their personal drama like Kodlak does.
That said, it does build a bit more personality as you rank up. You'll get some actual quests with stakes beyond "go kill bandits at location X," and the questline does eventually have an ending that matters to the guild's actual storyline. But if you're expecting Companions-level character depth and family stuff? Nah, that's not Oblivion's thing. The Mages Guild questline is way more story-heavy if you want that, and the Dark Brotherhood has actual narrative meat to it.
Honestly though, Oblivion's strength was never the "join a found family" angle - that's Skyrim's innovation. Oblivion was more about the weird stuff: House politics in Morrowind vibes, actual factional consequences, strange questlines. So maybe don't compare it to Skyrim's guild experience and just let it be what it is? You might find it refreshing once you stop expecting the Companions formula.