El Al certainly have a high threat to deal with -but before we go too far in saying we should copy them, bear in mind some factors make their job easier. For a start a large proportion of their pax are Israeli citizens. This means they know a great deal about them. On top of that many of their flights are to or from Israel -in which case the pax is either visiting relatives or has some good reason for going. The remainder can then be grilled as descibed above. A colleague of mine had that pleasure and while the process was thorough, it certainly wasn't polite and indeed was highly intrusive. For instance he could see the relevance of being asked where he purchased his suitcase but not whether he had a sexual relationship with a female member of his dive party.
His interrogation took about 50 minutes, and definitely made him choose a different holiday destination in future. Even with tens of thousands of extra trained staff, we still wouldn't have the resources for such a process.