Thank you Tobias,
“If one sees this as the purpose, then one should remain in sansara forever”
One sees this as the purpose WHILE in sansara (“Sure, there is enough reason for vipaka”)- all the while ever mindful of the greater purpose, Nibbana.
“All what is needed, is to stop the mistake of attaching to anything in this world” This is so, but also much easier said than done for all but Anagamis. Most, even of those on the Path, will have attachments. Maybe more, maybe less.
Much Metta