If they became part of a nation army, divided across the different units, and most of their men discharged after the war, then these organizations disappeared
Had the IDF adopted the Etzel tactics of bombing the British as you suggest that would probably cause immense issues in the next desert tank war fought in 1956
The Irgun didn't "vanish." Its violent, expansionist and terrorist ideology succeeded. It then took over the "state", making the old brand name redundant. Why would Menachem Begin need a private terrorist gang when he could one day command the entire military to achieve his goals?
And your argument about tactics is a pathetic diversion. The state adopted the Irgun's core ethos, a readiness to use extreme, disproportionate violence and terrorism for political ends. This is the "state" whose military ruthlessly attacked[0] its own "greatest Ally", an American naval intelligence ship, the USS Liberty including its crew, and later formalized its terrorist strategy of collective punishment into an explicit military policy, the Dahiya Doctrine[1]. The violence wasn't abandoned. It was industrialized. Instead of a terrorist bombing a hotel, Prime Minister Begin used the full force of the air force to carpet-bomb Lebanon and Gaza.
The Irgun didn't disappear. It just took over the "state" and evolved its terrorism by trading its primitive zionist bombs for high-tech fighter jets.
"Operation Cast Thy Bread was a top-secret biological warfare operation conducted by the Haganah and later the Israel Defense Forces which began in April 1948, during the 1948 Palestine war. The Haganah used typhoid bacteria to contaminate drinking water wells in violation of the 1925 Geneva Protocol."
https://en.wikipedia.org/wiki/Operation_Cast_Thy_Bread
Not to mention that Israel has dropped the equivalent of several nuclear bombs on a tiny open-air concentration camp with no possibility to flee.