How should authors interpret very enthusiastic editorial praise at submission?

I’m trying to better understand a dynamic I’ve experienced in publishing.

At the submission stage, I received extremely enthusiastic feedback about a manuscript. The language used went beyond polite encouragement and strongly emphasized its literary quality, originality, and importance. As an author, it was difficult not to read that as genuine belief in the work itself.

Once the book was published, reality was far more muted. The contrast made me wonder whether my expectations were shaped less by the book’s actual prospects and more by the tone of the initial editorial response.

So my questions are structural, not accusatory:

• How common is it for publishers to use very strong, glowing language during acquisition?
• Is this kind of praise sometimes part of standard communication rather than a signal of long-term confidence?
• How can authors better calibrate their expectations when the submission feedback is overwhelmingly positive?

I’d appreciate hearing how people with publishing experience interpret this gap.