No matter how much time passes; used to say that something does not change or happen despite the passage of time (often with a sense of frustration or surprise).
いつまで経っても君は子供扱いだね。
You're treated like a child no matter how much time passes.
いつまで経っても連絡が来ないので心配だ。
I'm worried because no contact has come, no matter how much time passes.
新しいシステムはいつまで経っても安定しない。
The new system never stabilizes, no matter how much time passes.
いつまで経っても慣れない仕事もある。
There are jobs you never get used to, no matter how much time passes.