That may well be true today, but it wasn’t always the case.
Historically, for example, see the Spanish fonts cut by Geronimo Gil for Joaquin Ibarra and the Real Academia edition of El Ingenioso Hidalgo Don Quixote de la Mancha, published in Madrid in 1780 — one of the finest editions of this seminal Spanish-language epic.
It features very upright acute accents (probably influenced by previous generations of French and Dutch fonts used in Spanish printing heretofore). To address the matter of harmonizing native accents, we find a much more exuberant and volante tilde (rather laying down the acute ;-).
But, as Nick points out, overall vertical dimensions may play a part in such decisions, on a case by case basis.