Because if we had observations of the future, we obviously would trust them more than models, But unfortunately, observations of the future are not available at this time.
"Kui meil oleks olemas vaatlusandmed tuleviku kohta, siis usaldaksime neid kahtlemata enam kui mudeleid. Aga paraku... ...ei ole tuleviku andmed meile praeguses hetkes kättesaadavad." (Naer)