Meaning of XばXだけY vs. XばXほどY

Question

X1ばX2ほどY is more common than X1ばX2だけY and seem to have similar meanings.

I've also seen X1ばX2だけY being used with X2 being used in both the present and past tense, and I don't think I've seen the past tense much with XばXほどY, and occurrences on the web seem to confirm that. For example 「売れれば売れただけ」turns up many hits, but 「売れれば売れたほど」only 4. Same for 「食べる」.

Can someone please clarify the differences in usage and nuance between the two patterns, and the two tenses for X2.

Edit: Since the past tense sounds unnatural to people, here is the transcript of the drama the example is from, in case context helps:

A: 僕の小説は面白いですか？

B: もちろんです。１５０万部突破ですよ。数字が証明しています。

A: 売れれば売れただけ面白いってことですか。

Answer 1

1. 売れれば売れるほど儲かる。: OK
2. 見れば見るほど美しい。: OK
3. 売れれば売れるだけ儲かる。: OK
4. 見れば見るだけ美しい。: Unnatural (at least to me)

In general, だけ can work similarly to ほど, but it implies the "degree" is somehow limited by the word before だけ. For example 車を買えるほどのお金 is "money enough to buy a car (or more)", whereas 車を買えるだけのお金 is "money necessary to buy a car (and not more)". やれるだけのことをする means "to do what someone can do (but not more)".

Such difference is often not important, and ほど and だけ are interchangeable in sentences like 売れれば売れる{ほど/だけ}儲かる, 勉強すればする{ほど|だけ}賢くなる or 年を取れば取る{ほど|だけ}走るのが遅くなる.

But I feel using だけ may imply "unless X happens, Y will not happen, either". 見れば見るだけ美しい sounds unnatural to me because it's like saying the beauty of something is limited by the observation time. Likewise, 聞けば聞くほど悲しい話 neutrally describes how sad the story was, while 聞けば聞くだけ悲しい話 tends to be used when the speaker doesn't want to listen to the story because he doesn't want to feel sad.

As for tense, Xれば + Xほど/だけ almost always takes a verb in present tense regardless of the tense/aspect of Y. "売れれば売れただけ" sounds unnatural to me.

5. 売れれば売れるだけ儲かった。
6. 見れば見るほど美しかった。

If ～たら is used instead of ～れば, something like 売れたら売れただけ is fine.

7. 売れたら売れただけ儲かりますよ。
8. 売れたら売れただけ儲かりました。

Answer 2

The only answer I can give you is the translation of page 299 of 日本語表現文型辞典 od ASK publishing.

• Both express that: “the more the thing expressed in the first sentence is strong, the more the expression in second sentence gets strong too”. The ば that expresses the condition is frequently omitted.

• (~ば)~ほど expresses a situation in which a tendency grows propotionally stronger 「〜ば、もっと/むすます」

• 〜ば〜だけ is frequentlt used in the form 「〜ば、動詞のた形＋だけ」「〜ば、それだけ」「〜ば、動詞のた形＋ぶん」

For example 磨けば磨くだけ綺麗になる／磨いただけ、綺麗になる。

Or 磨けば、それだけ綺麗になる／磨いた分だけ綺麗になる