Why past perfect tense not used in this sentence?

Question

I read this sentence from the book Harry Potter:

Harry was frying eggs by the time Dudley arrived in the kitchen with his mother.

According to my dictionary, prep by here means before or not later than a particular time. It seems to suggest that past perfect tense should be used for this sentence. It would become:

Harry had been frying eggs by the time Dudley arrived in the kitchen with his mother.

That means Harry kept frying eggs till Dudley arrived in the kitchen with his mother.

However, I am confused by the original sentence. Does it mean Harry was still frying eggs or he had done with frying eggs when Dudley arrived in the kitchen? If he had done with frying eggs when Dudley arrived in the kitchen with his mother, why is the past perfect tense not used？

Answer 1

By the time is used here to mean when - leaving aside any nuances.

By the time is an expression. You can't just extract by from it and try to analyse its meaning. You have to take the meaning of the whole expression.

So Harry was frying eggs when Dudley arrived....

The author might have written:

Harry had been frying eggs....

But use of the past perfect makes the action seem more remote and here the author is trying to draw the reader into the action by making it more immediate. In other words, it's a literary device.

It's like telling a friend:

I was sitting at the table when the legs suddenly collapsed.

It's the way people talk when they want to convey the immediacy of a situation rather than trying to set it back in time.

Writers are generally more concerned with the impact of their words than their grammatical constructions.