How does まで work in ～なまでの／～なまでに?

Question

I ran into the following sentence in a video game called 善人シボウデス:

俺の腕は暴力的なまでの勢いで、後方に向かって手{た}繰{ぐ}り寄{よ}せられた。

I decided to look online, and I found similar examples, some of which used に rather than の:

危険なまでに美しい

異常なまでのこだわり

Dictionaries describe まで as a particle. Depending on the usage and which dictionary you check, it seems to be described as a 副助詞, or sometimes as a 格助詞 or 終助詞.

It looks to me, though, like まで is a noun that means ほど in these examples. I think I could substitute ほど in place of まで.

But dictionaries don't appear to list まで as a noun.

1. Am I right to call まで a noun in this usage?
2. Am I right that まで means ほど here?

If not, how would you describe it?

Answer 1

You are right about that ほど can be a substitute for this kind of まで in these phrases. However, they are not nouns. This まで is 副助詞 and this ほど is also 副助詞.

Dictionaries (eg. 大辞林, 大辞泉) define both the noun meaning and the 副助詞 meaning of ほど.

までに is considered a collocation（連語） in these dictionaries. So, they contain the entry of までに. According to the second definition of までに presented by デジタル大辞泉,

まで‐に【×迄に】

２ 動作・作用の至り及ぶ程度を表す。…ほど。…くらいに。

ほど can be substituted for まで in までに.

There is no entry of までの in these dictionaries. But I think, まで in までの is also 副助詞 (and this の is 格助詞) and ほど can be a substitute for this kind of まで, because the second definition of 副助詞「まで」 is almost the same as までに's second definition above.

まで【×迄】

２ 動作・事柄の及ぶ程度を表す。…ほど。…くらいに。

Besides, I think that both 〜なまでの／に and 〜なほどの／に sound natural to most native Japanese speakers, or at least to me.

However, some words match までの／に more than ほどの／に in some contexts, and some other words match ほどの／に more than までの／に in some other contexts. Unfortunately, I can't find a good example of it right now, though.

About the difference in nuance between 〜なまでの and 〜なほどの, I would say, 〜なまでの implies "reaching a 【危険な／見事な etc.】 degree," while 〜なほどの implies "being around/about a 【危険な／見事な etc.】 degree." But, I asked two native Japanese speakers (adults) "Do you feel any difference between 〜なまでの and 〜なほどの?" One answered "Hmmm......let me think......Yes, somewhat." and another said "Ehhh......No, not particularly." So, I guess that the difference is not obvious, or there is no difference for some people, when both phrases work fine in a sentence.

By the way, くらい can be 副助詞 either. Here are 名詞「くらい」 and 副助詞「くらい」 presented by デジタル大辞泉. ばかり and だけ are 副助詞 too, in this pattern of phrases.