I know Minato escaped, but Obito's warping can go faster, as he noted before warping to Minato's location.
Obito already stated that he can use Human Path:
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Madara already taught him about the Six Paths Jutsu:
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Rinnegan lets you use all the Paths including Gedo the 7th Path:
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Why wouldn't he be able to use the others?
Itachi can't spam Amaterasu, he may have the chakra problem figured out (Tsunade) but his vision still deteriorates.
And if Obito gets hit, he can simply phase through it like he did when he got hit with it when it came out of Sasuke's eye or Shinra Tensei can blow away the flames.
And he still has Mokuton.