The difference is that with Doom it was multiple years of various writers all using him outside of the FF book and making him be a major villain each time while in the case of Osborn it was Bendis pushing a favorite character and using his editorial power to make it a company wide mandate that Osborn be the #1 villain in the MU.Positioned by writers, correct? Ain't that the point?
If a buncha Osborn-stans wanted to follow Bendis lead after his late '00s run and kept Osborne positioned as the center of Marvel earth, then in 2028 some young 10yr TheGodlingJr. will be talking about Osborne the same way you were talking about Doom in 2008, both citing a 20 yr run of writer decisions for your perceived normalcy lol.
i.e. That normalcy will always evolve, depending on whose behind the scenes like a writer, editorial, or now Disney and MCU. Classic example spanning 56 years is Gwen or MJ as the center of Peter's world. Depending on your DOB, one will resonate strongly and the other may feel blasphemous
Doom's placement was organic.