By the autumn, Germany was bombing Britain's cities

[lagoo]

By the autumn, Germany was bombing Britain's cities almost daily, convinced the British would eventually crack.

source: TV documentary "world war II in color"

Does it mean 'Germany was bombing Britain's cities from some day to the autumn'?
In which case, can I modify it as 'By the autumn, Germany had been bombing Britain's cities almost daily'?

 

[tedmc]

By the autumn, Germany was bombing Britain's cities almost daily, convinced the British would eventually crack.

The second part of the sentence does not seem to match this first. Is that correct?

 

[jutfrank]

By the autumn, Germany was bombing Britain's cities almost daily, convinced the British would eventually crack.

The second part of the sentence does not seem to match this first. Is that correct?

It's fine. What seems wrong to you? Germany was convinced the British would crack.

 

[tedmc]

You could insert 'that' after 'convinced', but it's not essential.

The "that" makes it clearer. I read "convinced" earlier as a transitive verb.

 

[Tdol]

It's fine. What seems wrong to you? Germany was convinced the British would crack.

They were wrong.