If we believe in our Player Development... it's a temporary hiccup to give up all those years of team control for 1 year for Ohtani and a comp pick? That feels like a stretch.
So Fangraphs treats net present value of prospects like an annuity that compounds annually at 8% interest. If you follow this formula, 114 million in future value that starts paying dividends in 2024 would have a value of ~87 million in 2023. If you buy Ohtani as a 10+ win player as both a hitter and pitcher next year, then he'll be worth 70 million in surplus value (~100 million in performance - 30 million in salary) in 2023. When you factor in the fact that Ohtani's wins are providing value for a team that is likely in the playoff hunt, and the pick we're getting, I think that the trade is pretty close even for a rental. The better situation is obviously that we sign him to an extension, but even if we aren't able to agree to one it's not bad. Maybe it's a stretch that offloading that many prospects is temporary hiccup, but it's actually decent value.
The assumptions made here are that, Ohtani will set the record for largest arbitration award in 2023, and it still won't come close to his actual value as a player. If Ohtani's arb award deviates from this it will change the calculus pretty substantially.