The bigger the vehicle the more altitude that is needed to deploy chutes. The bigger the vehicle the proportionately heavier the chutes need to be because they need to spread out more and they need to be stronger.
Furthermore, most commercial aviation disasters occur at low altitude and the ones that happen at high altitude tend to be too catastrophic for chutes to be of value. (If something bad happens at high altitude that doesn't destroy the plane it tends to make it back.) Off the top of my head I can only think of three crashes where they could have used chutes--two where the hydraulics were damaged by high energy events (and would the chutes have worked properly??) and one fuel failure due to hijacking.
Furthermore, most commercial aviation disasters occur at low altitude and the ones that happen at high altitude tend to be too catastrophic for chutes to be of value. (If something bad happens at high altitude that doesn't destroy the plane it tends to make it back.) Off the top of my head I can only think of three crashes where they could have used chutes--two where the hydraulics were damaged by high energy events (and would the chutes have worked properly??) and one fuel failure due to hijacking.