Humans have G limitations that soil samples don't
Apollo capsules had 3 chutes and could survive impact if one failed (which happened at least once). The impact wouldn't have been survivable if 2 chutes failed, IIRC. While humans can survive at least a 40G impact in the transverse direction (front to back in a properly designed seat), the capsule itself wouldn't.
As Bill Lear told his engineers when they were designing the first Lear Jet, "If you don't include it in the design, you don't have to worry about the backup, either."
Or, as the late great British engineer and test pilot Geoffery de Havilland said, "Simplificate and build in lightness."
Or, as Scotty stated, "The more complicated it is, the easier it is to break."