> They've had the capability for decades. So why hasn't it happened?
The same can be said for any conflict in which one side has overwhelming capacity and does not choose to engage on it for various reasons. But yes, diplomacy and public pressure actually matter a lot, as evidenced by the fact that Israel spends billions of dollars in state propaganda and funding political campaigns in the West to continue to receive military aid and avoiding sanctions.
You are saying that Israel has shown itself to not be susceptible to international pressure on existential questions yet it engaged for decades in political and diplomatic action to be where it is today; it was not looked at that favorably by Western powers even a few decades backs. And it understands that apartheid South Africa was not on anyone's radar for decades until it was. AIPAC and other lobbying agencies fund hundreds of political campaigns in the US in order for this to happen.
So yeah, if in five years' time the Democratic Socialists end up overtaking establishment DNC Zionists and get their share of power such that they allow BDS to work and stop military aid then Israel is going to have a much more difficult time, as evidenced by their desire to have the US engage Iran without them participating directly because they are not actually as powerful militarily as they project themselves to be.
> Sure there might be sanctions, etc. but there will always be someone willing to work with them. And their foreign military sales make sanctions not exactly straightforward for e.g. Germany.
That works until it doesn't, much like how China did not dominate on renewable energies until it did, or how proprietary Unix dominated the server market until Linux appeared. It takes remarkably little time to turn a country into a pariah state. For the past two decades Germany theorized that economic connections to Russia would prevent them from doing anything stupid regarding Ukraine.
And Israel does not just have to care about external issues. Economic sanctions hit economies hard, and even a recession is enough to turn the tables against candidates during election years, so given that certain political parties are the ones who hold the cards at any time, they are not keen to lose elections.
Also Israel depends very much on its network of high-tech companies, companies that are extremely sensitive to any sort of sanctions regime or any loss of trust such that no amount of lobby money suffices to get profitable military or high-tech contracts.
And once Israel is politically and militarily isolated it becomes a much easier target against rivals in the Middle East, so being politically associated with the West is very much a matter of survival. In this sense they have all the time in the world to perform their campaign of ethnic cleansing to restore Eretz Israel.
None of what I'm saying is speculation, this is very much what political analysts in Israel say and have been saying for decades. The only difference is that now that liberal Zionism is dead and has been dead since the death of Itzak Rabin and the demographic explosion of the settler movement there's really no one to stop them from proceeding with these plans.