In addition, Sa'ar 5 incident is not a good example becuase it's systems, for all intents and purposes, were turned off.
There is no foolproof, total shield for protection. But clearly, given the proliferation to other navies (whose own experts are looking at the trade-offs and the effectiveness of the system) to this date, the AEGIS system has to be considered about the best available. Perfect? Nope, but any adversary is going to have to work very hard and be willing to commit and risk significant resource and assets to defeat it.
In the end, that's what it boils down to. How much does one side have to invest in a defensive system (and are they willing to make that investment), and then, how much does the other side have in terms of assets and technology to invest in overcoming those defenses, and are they willing to risk those assets in doing so.
For a major US task force, SAG, PHIBRON, or Carrier group protected by AEGIS the aircraft and or surface combatant investment is going to have to be very, very high, both during the engagement, and then thereafter (whether they are successful or not) when the inevitable retailiation comes (which will have to go through the same trade-off, risk, and investment calculations).