Question

would have done应该不仅仅指虚拟语气吧，是否应该还有推测的含义

Answer 1

“would+have+done”虚拟语气，表示对过去事情的假设，意思是“本来会做”。
1.
I
would
have
told
you
all
about
the
boy's
story,
but
you
didn't
ask
me.
我本来会告诉你这个小男孩的故事，但是你没有问我。
2.
Without
your
help,
I
wouldn't
have
achieved
so
much.
没有你的帮助，我是不会取得如此大的成绩。
另外，would
have
done的确也可用于不是虚拟语气的句子：
1.
Jordan
never
would
have
done
that.
乔丹永远不会这么做。
2.
Almost
everyone
would
have
done
it.
几乎大家都会做。

Answer 2

would have done 就是 表示 对之前事情的推测 说判定 更准确 推测 是表示可能性 那是 could have。
但你有个 假的 虚拟条件 if , without, 的时候 变成了对虚假条件的判定 就变成了虚拟语气。