Hi Ostap77,
I beg your pardon for my breaking in your conversation but in my humble opinion there are two different connotations of the expression in question.
1. pack in = attract a large number of
The new music group is packing the crowds in. - The new group gathered crowd. - На новую группу собираются толпы.
2. pack it in = stop, throw (work)
Why don't you pack in, before you kill yourself. (M. Lampell) - Why do not you stop before you kill yourself?- Почему бы тебе не остановиться до того, как ты убьёшь себя?
She didn't like her new job at all and was thinking of packing it in. - She did not like her new job, and she thought to leave. - Ей не нравилась её новая работа, и она думала уйти.
I consider it as very paradoxical.
Really, English is a very strange language.
V.