There is no contamination or deep wear and new genuine pads from last year behave the same. I am in course of changing SRAM pads with compatible Swissstop and I am just checking my understanding about how disk brakes work.
Bed-in seems to result, indeed, in depositing a layer of pads material on the disk, which improves braking performance. My understanding was that bed-in is done once for the whole life of the pads, but my SRAM rotors seem to lose pads material every time I wipe them with alcohol, then need to repeat bed-in.