That link will become true next April with Air Madrid flying MAD
2x weekly with A310, and with good connecting times to South America.
As for Pluna, I think a non-stop flight from Israel to South America is not possible right now. The market is almost purely tourists and VFR (Visiting Friends and Relatives), which means very low-yields. Besides, this kind of people usually go for the cheapest option, no matter if they have to change planes once or even twice until reaching the final destination. And loads during the non-holiday months should be quite bad.
Pluna right now has only one 767-300ER which is only used for the MVD
3x weekly rotation. Apparently they have been doing very well with this route, and are even considering getting a second plane to serve it daily. Their other planes by no means can reach TLV
- 757, 732, 733 and ATR-42.
The only big player in the South America-Israel market is the Sochnut Ha'Yehudim, the Jewish Agency, which sponsors trips to Israel for Jewish young people (Birthright Program), and Aliyah (immigration) programs. The Sochnut always wants its people to fly El Al, at least on one segment of their routes. Currently they choose Iberia, because of the codeshare with LY
on the MAD
Airlines have rights to many places they don't serve. LY
has rights for Rio de Janeiro, and they have never flown there, same for EK
and many others.