Bron or GS will only die off by the time those guys contracts are off the books. Bron has another 3-4 years of dominating left. Plus you're forgetting that Kyrie and whoever else they add will only get better too. Meanwhile, GS is on the other side 3peating.
If you cant land a star this offseason I'd trade IT for a top pick while his value is sky high and look to build with the young guys (Fultz, Porter/Mamba) and role players (Smart, Crowder, Olynyk, Rozier).
He's great, but he's not going to win the East at 33-34-35-36 after already 7 straight Finals man.
Not to mention, Kyrie/Love etc would have to survive another 4 Finals runs on top of the first 3. At some point, someone breaks down. Maybe not next year, but well inside the 3-4 you are mentioning.