Montreal Convention won't do anything here. No loss of life or limb. No loss of luggage. EC 261/2004 doesn't apply as it applies only to the operating carrier and so that was EK on the xEU segment.

Had EK been delayed and that caused a misconnect, it would have been the ultimate delay which would have been used to calculate compensation, but that isn't what occurred here.

This is no way calls into question the value of a single ticket. It simply calls into question the mistaken belief that somebody will always pay for your hotel if you are delayed. That is a purely EU (and Israel) thing unless it's due to a circumstance within the carrier's control such as a mechanical.

In the vast majority of the world, when things go wrong, they go wrong. If it costs money, it costs money. If it's a risk you can't afford to take, you insure it or don't travel.

Multi-segment tickets across multiple carriers to destinations with limited frequencies are prone to problems even today.