Yes the flight crew is the key factor in the majority of crashes. It's for this reason that two big innovations are largely responsible for the massive drop in fatal accident rates since the 90s (there hasn't been a crash of a heavy, loaded with passengers at least, in the US in over 20 years - think about it... 20 years, and that was a pilot-induced rudder-fin failure).
The first and biggest is Crew Resource Management theory, which started to be implemented in the West in the 80s. CRM was so successful that its concepts have spread far and wide outside aviation, from policing to surgery. The other one is Flight Management Systems and the two dimensional map navigation display made possible by the "glass cockpit" (also in the 80s). It's hard to exaggerate how much 2D moving maps reduced crew workloads in terminal areas and on approaches, by reducing the dependence on a pilot's internal mental "map making" abilities to maintain situational awareness.
Fatal crashes caused by system failures are exceedingly rare, because at the certification level, system design requires a mathematical probability of better than one in a billion of a component failure leading to an airframe loss. MCAS can be discarded as a Black Swan event, a culmination of a set of very unique circumstances and decisions at the certification and development level (I mean, so unique that the project chief test pilot was charged criminally for hiding information from the FAA). MCAS can be thought of as "pilot error" induced by a bad configuration that slipped through the cracks you could say, but which some crews could have coped with.
Double and triple systems redundancy is required to maintain this less-than-one-in-a-billion probability of disaster. It's not perfect, but it's the main reason airplanes don't fall out of the sky regularly when components fail (and things are breaking down on complex aircraft all the time as you can see in an airline's dispatch delay rate - those regular delays leaving the gate are usually because the plane arrived with something broken that has to be fixed on the spot).
"Automation" in itself? Yes automation could probably be said to have prevented some disasters, but in the bigger scheme of things, not as much as something like CRM. FADEC makes engine operation a little easier and more convenient for the crew, but it mostly drives costs down. Fly-By-Wire and other system automation controls? They help reduce crew workload overall, and maybe cover for sloppy flying from time to time, but they are also mostly cost reduction drivers (FBW eliminates a massive amount of hardware). On the C-Series/A220, the systems automation level is just about at the pinnacle of current development, and the main benefit (and selling point) is a huge reduction in maintenance man-hours, more than safety.