How did « comme » + « bien » compound to signify « combien » (quelle quantité, quel nombre)?

Question

How do comme and bien semantically appertain to comme's definitions below in 2021 Modern French? Neither of them signifies the definitions below.

1. Dans quelle mesure, à quel point.
2. quelle quantité, quel nombre.

combien | Usito

11e s. (in NPR); de l'ancien français com « comme » et bien.

COMBIEN : Etymologie de COMBIEN

Composé de l'a. fr. com (comme*) et de bien*.

Answer 1

The French combien is unique among the Romance languages.

All of them inherited a word from the Latin quantus ("how much/how many/how big"). It is quant in French, Catalan and Occitan, quanto in Italian and Portuguese, cuanto in Spanish, cât in Romanian, and so on.

However, the French quant was competing with its homonymous quant¹, inherited from the Latin quando ("when"). The reason is that unlike the remaining Romance languages, French turned the Latin last consonant D into a T to match the way it was pronounced. Spanish distinguish cuando from cuanto, Italian quando from quanto, Romanian cât from când, and so on but there was a clash in French.

Because of this collision, French had to find an alternative. It replaced² the first quant by the periphrasis com bien (i.e. comme bien / comment bien) that eventually merged into the new adverb combien. Here comme comes from the late Latin quomodo (literally: "what way", i.e. "how") and bien from the Latin bene ("well") so combien literally means "how well".

Some linguists think that this creation might have been influenced by a Germanic adstrate, because of a similar construction in it: German has wie viel ("how many") and Dutch hoeveel ("how many/how much").

¹ _{Later, quant was modified to quand to show its Latin roots but without affecting its pronunciation. We still pronounce T in Quand elle viendra: /kɑ̃tɛlvjɛ̃dʁa/.}

² _{This quant only survives in the idiom quant à.}