If Egypt had launched another invasion but this time post 79' with Iran joining in post 79' coup and Saddam's military, they would have been successful and probably driven the Jews to the Seas like the prophecy.
Even if Israel relied just on conventional weapons, there was virtually no possibility of eliminating that nation entirely. In 1973, Egyptian generals never thought they'd be able to advance clear across Sinai.
What might've been possible though, was a prolonged bloody stalemate sort of like the Iran-Iraq war. Had Israel refused to return Sinai, even in exchange for a separate peace with Egypt, Cairo would've had no choice but to rearm for another conflict. To do that, they'd have to remain on good terms with the USSR and get as much money as possible from oil producing states--which probably wouldn't have been difficult if deadlock was due to Israeli intransigence.
In fact, had that been the perception Egypt probably could've obtained advanced arms from France as well as the USSR, such as the F-1, in great numbers. In the OTL Cairo had a deal to get 200 F-1s, which would've represented an enormous improvement over its MIG-21s, and available MIG-23 variants such as the MIG-23MS. The deal fell through after Egypt opted for peace beginning with Sadat's trip to Jerusalem in '77. But if intransigence affected Israel's international standing and increased sympathy for the arabs, Cairo might've been able to get the Jaguar as well as all the F-1s it needed.
With Egypt still in the arab fold in '79, attention would've remained focused on Israel, and a high probability of war might've induced Saddam to lay off Iran, so Iraq could participate in syria again.
More and better weapons, plus plenty of Iraqi and Iranian reinforcements, might've made a big bloody stalemate possible sometime in the early '80s.