Here, わけ doesn't mean reason. It emphasizes that something is a natural result and can be omitted.
Ex:
- 彼があまりにできるからヘッドハンターの目に留まったというわけだ。(He came to the headhunter's attention because he was so competent.)
Here, 〜ヘッドハンターの目に留まった。 is also fine.
- No wonder he didn't get my e-mail. I didn't send it! (彼がメールを受け取らなかったわけだ。私が送らなかったんだから!)
- This building is really solid. No wonder it survived the earthquake. (本当に頑丈な作りの建物ですね。あの地震にも耐えて残ったわけだ)
- そういうわけだ。(That's the story. / That's what this is all about.)