In Naruto, a number of ninjas have become jonin, such as Neji and Kakashi. Does every ninja who becomes a chunin by definition become a jonin if they live long enough, or do some remain a chunin forever?
No not everyone will become a Jonin. As you may have noticed, some ninja like Naruto don't even become Chuunin. Naruto is a rare example however.
In order to become a jonin, a ninja must be extremely skilled. Jōnin are generally able to use at least two types of elemental chakra, some genjutsu, and above average taijutsu skills.
They are usually also appointed to A and/or S ranked missions alone while those under the Jonin rank usually go with a team, or not at all.
If you think about this from a real world military viewpoint, it is like asking if every recruit becomes a commanding officer. The answer is no. Also as related, keep in mind that not all academy students become Chūnin, so that might apply here too.
And as per the wiki
It is as of yet unknown what one has to undergo to become one. It is mentioned that jōnin are appointed, however there was mention of a Jōnin Exam in the anime's Kurama Clan Arc. When a ninja becomes a jōnin, they may be assigned a three-man genin team to supervise.
And then there is also this guy.. Kosuke Maruboshi who even though by choice, has been a genin for over 50 years. This could also apply to your question.
Some become Chunin, some become Jonin. No one knows how they become Jonin, but in the Anime both appointments and exams are mentioned as a way to become Jonin. Only power- and skillful ninja will become Jonin.
I know it's like a ranking. You have to undergo an exam or a test to be one ranking higher... I don't know if this sequence is correct: genin, chuunin, jonin... In the 1st episode of naruto shippuuden, it is known that naruto is the only one that's still a genin, others were chuunin and jonin. There are other ninjas that maybe are still on the same level or ranking.