A Latin text face needs a few hundred glyphs. A Devanagari face that sets real text needs several thousand, and most of them are conjuncts that only exist because two other letters met.
The arithmetic
Every conjunct is a design decision, not a mechanical combination. Which ones get a dedicated form, which are composed, and which are quietly avoided by rewording: that set of choices is the typeface.
Eleven years
Nine of them were conjuncts. The two that were not were spent on the numerals, which nobody notices, and on the question of how the face should behave beside Latin, which everybody notices and nobody can articulate.