That is my point. Talked to common sense by who exactly? I threw out Warren because she is a nationally known figure, but I recall quite a few other names circulating as potential heirs to Obama. Gavin Newsom, Antonio Villaraigosa, Andrew Cuomo, Deval Patrick. For candidates with strong localized appeal but not necessarily broad national recognition, you need establishment donors to kickstart their campaigns into the national spotlight.
Clinton was the presumptive nominee until Obama came out of nowhere, a relatively unknown national figure prior to his campaign, and beat her with a resonating message and superior ground game built from a broad reaching coalition of advocates. For this election cycle, any of the names I previously mentioned were potential threats to her for a variety of reasons, and you can be sure the Clintons were working the establishment hard to make sure she didn't face Obama 2.0.
Why did Obama make Clinton his SoS and advocate for her over any of the candidates I previously mentioned. That is open to speculation, but I would hardly classify her as his heir apparent.
Given the names I just rattled off, how did the only credible threats to Clinton become Webb and Sanders, two DINO's beyond the reach of the establishment. Does that not strike you as oddly coincidental?