Thinking that a triple is a weakness that you need to "grow out" of is just a false assumption. For example, I love the feeling of pushing the big gear on the flats, but when I do, my knees don't love me. Hence, if I was mashing up the hills in a bigger gear, the same would happen.
I guess I am not that strong, since I am small and short. Not getting any younger, either! I spin up everything. That said, I live on a fairly big hill that people train on and most rides I do have climbing. At one point, I considered getting a compact and then I ended up buying a new bike with a triple. I don't regret it. In fact, I love my granny gear and although I use it less as the season goes on, I do use it.
My husband, who is a very strong rider has gone from a double, to a compact, to a triple. He doesn't *need* it, but you can be sure he uses it.