The only argument against this is that park-adjusted numbers and elite defense are things that bore writers. So while he should be in the conversation, these arguments won't get him anything more than complimentary 2nd place votes.
I was thinking pretty simply myself, just an objectively significantly better offensive year from Bryant, while both are comparably strong defenders at premium positions. The park adjustment is an interesting factor but that point might be undermined a bit by the fact that Seager is better at home and Bryant is better away (again significantly, in both cases). You might say that's fallacious and could definitely argue that Seager would be even better at home and Bryant would be even worse at home in neutral park settings, but I didn't even think about that initially so I give you credit for bringing it up. I don't consider Seager elite defensively personally. I don't really look at defensive metrics given their notorious lack of reliability. I do think however that it's safe to say both are quite strong. The assessment of Seager being elite requires some support.
i said exemplary i used that as an example, never said it was the standard you took it out of context to make try and make your point the three you cited were exceptions, not the rule and i said it was possible, just not likely