Although Pikachu (https://collectorpricing.org/golden-pikachu-card/ https://collectorpricing.org/golden-pikachu-card/) won't be replaced, Ash really can (and I

Although Pikachu (https://collectorpricing.org/golden-pikachu-card/ https://collectorpricing.org/golden-pikachu-card/) won't be replaced, Ash really can (and I wish he gets replaced). Does Pikachu (the species) even need to be with Ash in the first place? It is a common Pokemon species rather than a unique one like the legendaries. When Digimon wish to play the Agumon card again, they do it with a different Agumon in Savers since they're not frightened of having multiple human MCs per generation (same species, different individual). Why is that not possible with Pikachu?