Well performed research takes time.
There are many stages during the process:
initial ideas, literature searching, study design, ethical approval, data collection, data analysis, manuscript composition, journal submission.
An individual trainee faces considerable time constraints to progress through all these phases in any six month post.
Research collaboration will overcome the problem of rotating out of a department before project completion because collaborators can continue with projects until completion.
In contrast, completing research alone and within finite time frames is far harder