Solution

Traditional file systems have many drawbacks.

Statement $1$:

Data inconsistency can occur because the same data may be stored in multiple files.

So, statement $1$ is correct.

Statement $2$:

Accessing required data is difficult because special programs may be needed for each task.

So, statement $2$ is correct.

Statement $3$:

Data isolation occurs because data may be stored in different files and formats.

So, statement $3$ is correct.

Statement $4$:

Atomicity problems can occur because updates may be incomplete if a system failure happens.

So, statement $4$ is also correct.

Therefore, all given statements are drawbacks of file systems.