The Rambam is famously quoted as saying that every person has the potential to become like Moshe Rabbeinu. But compare that with a piece taken out of a shmuz given by Rav Shlomo Freifeld Ztz'l:
"The Chovos Halevavos says that there is a cheshbon hanefesh, a way of introspection, "al mah sheyeish biy'cholto mima'aseh ha'avodah (on what is in his ability to do in his service of Hashem)." A person should ask himself, he should think and question, he should take stock of who and where he is regarding his avodah, his serving the Almighty. He should ask himself honest questions. What can I do? What is available to me? What are my abilities? What is realistic for me? A person can wake up in the morning and say that he is going to be the next Chofetz Chaim, but that's just self-deception, It's not realistic. The Chovos Halevavos tells us to be realistic. Where am I? What's my situation, my predicament? What can I accomplish in my avodah?"
So is Rabbeinu Bachya arguing with the Rambam? Do we, or do we not, have the potential to become like the Chofetz Chaim / Moshe Rabbeinu?
We do. Just not today. Today we have only the potential to become..... OURSELVES. If we keep doing our hishtadlus according to where we are holding, then our potential will keep rising and we will rise along with it. Our potential can expand to amazing levels. We just need a little patience. Hashem is happy with us doing what we can. We should also be!