An all-in-one solution would be far too heavy. Splitting the tasks up makes a lot of sense. Having all the equipment onboard to drill cores, quickly analyze them, decide if they're worth keeping, and then putting samples in containers is enough work for one rover.

* Storing all the samples onboard means a larger and heavier rover

* Mass budget squeeze means no more helicopter

* The return requires a ground launch from mars, so no more SkyCrane delivery system

Perseverance, obivously, has onboard instruments to analize the samples before dumping them on the ground

Because the powers that be would have deemed a real plan as too expensive.

Agree, the decision to drop samples on the ground doesn’t make sense to me. Store them in the rover. Much easier to find them all in one spot later.