No new uploads - zero sales.

Is it necessary to upload new items every week now to be visible for buyers?

Absolutely! For me sales dry up completely, if I don’t upload for a couple of weeks or more.

I think it depends on your items and how big your portfolio is. If you’re producing music in a saturated genre you’ll probably have to upload more often than if you compose more specialized music.
I have uploaded one track the last 7 months and still get sales everyday, but maybe I would get more sales if I uploaded more often?

Actually a very strange question. If you work then you earn money. xD