Actually, I don’t think that zoom have any kind of technological improvements than the other companies you mention, as Jitsi proves, making a videocall and screen sharing app it’s not really very difficult, as the building blocks are already stablished and it’s a matter of how you join them. Zoom make the choice to try to circumvent some security things to be able to appear less hostile for the user, and it seems that it was worth it. Several other things (integration with third party calendars, conference and seminar tools) are the ice in the cake.