As someone who doesn't know anything about baseball, why does Ohtani only have one MVP at age 29 if he is so amazing?
Ohtani has only been OHTANI for two-plus years, and in that time he's won one MVP and finished a legitimate second behind one of the most astonishing offensive performances of recent years (Aaron Judge last year).
Before 2021, Ohtani had three years where he was respectively good, decent, and awful. Before that, he was in Japan.
...
Now, how dominant is he actually being, in terms of
value, rather than the impressive breadth of his skills?
In 2021, Ohtani had 8.9 WAR, leading the AL by 1.7 WAR (about 19%). The NL leader was 1.2 WAR behind Ohtani (13%). At this point, I no longer consider the AL and NL to have any meaningful differences and consider there to be one league - there's no longer any justifiable reason to consider them to be separate (in many ways, there hasn't been for decades).
In 2022, Ohtani did not lead the league, finishing 1.0 WAR behind Judge (who had a 9% lead).
In 2023, Ohtani has 6.2 WAR so far, for a team that has played 90 games (55.5% of the season). Prorating that out over the rest of the year would put Ohtani at 11.2 WAR. The runner up, Ronald Acuña, is at 5.0 WAR in 87 games - prorated to 9.3 WAR. That would give Ohtani a lead of 1.9 WAR (17%).
Over three years, Ohtani would have 29.7 WAR. The next five (as far as I can tell) are Judge (21.3), Soto (19.5), Goldschmidt (18.9), Ramirez (18.8), and Betts (18.1). That's a pretty huge lead. Of course, this is cherry-picked to favor Ohtani - a four-year look would be different, as Ohtani was replacement-level in 2020 and good but nothing special in 2019.
This also relies on trusting WAR to the decimal - I don't think WAR can truly do that, but it's likely off in either direction somewhat randomly, so I'm not going to worry about it.
I do not believe there is any value in Ohtani being both a pitcher and a hitter - in theory it gives you an extra roster spot, but because the extra spot is going to be filled by a replacement-level player, I don't think it really adds more value than a tiny handful of runs, at best. Ohtani's value is simply the sum of his value as a pitcher and a hitter - nothing more.
In summary, I think Ohtani has been, over his most favorable stretch, about 25% more valuable than any other individual player. I don't know how that compares to McDavid, and I have no clue how that compares to Mahomes (I have zero interest in football). But that, numerically, is how dominant I believe Ohtani has been. It would be interesting to compare that to past players' best stretches.