Dear Aditi,
It appears that you have confused between the concepts of "performance" and "potential".
There are two definitions of the word "performance". These are given below:
Definition with respect to the past: - any recognized accomplishment
Definition with respect to the role: - process or manner of functioning or operating
In general, when we talk about performance, we refer to the past.
In contrast, "potential" is for the future. It is defined as the inherent capacity for coming into being.
In the 9-box matrix, there could be a situation wherein an employee may not perform and incidentally, he/she may not have the potential to grow. The possibility of this kind could be rarest of rare but cannot be ruled out per se.
When the management models are designed, these are designed for all types of situations. Their applicability is universal and the designers cannot rule out any possibility. If the employee gets into the "LL" box, i.e. low-performance and low-potential situation then it shows poor recruitment practices. A robust recruitment practice is expected to assess a candidate's ability to perform and also check whether the candidate has the potential to grow. However, occasionally, the recruitment team is under pressure to fill the vacancy and they may ignore the candidate's ability to grow. But at the same time, they rely on the performance at the previous organisation and believe that the candidate could deliver the same level of performance.
The "LL Box" syndrome is the reflection of the poor training practices in the organisation. The training department must focus on elevating the performance of the employees. However, self-obsessed HR/Training professionals concentrate more on the method of the delivery of the training and also the ability of the trainer to obtain "excellent" feedback from the participants. Moreover, they also just stop at taking feedback and do not do any follow up after the training.
Anyway, a 9-box matrix for matured organisations. It is not child's play. The implementation of 9-box requires the hiring of a consulting agency as well.
Thanks,
Dinesh Divekar