Mausoleum Turnkey: this card requires great graveyard manipulation and this set is not a graveyard-focused set
The McDonald's Pikachu will never be a high-value card on a per-copy basis, precisely because the supply at every grade level, but especially at PSA 10, is so astronomically large that demand cannot create meaningful scarcity-driven premiums
Because it casts a whole bunch of spells for free at the beginning of your Storm turn, because almost all of the effects are Suspendable on turn one, and lastly, because almost all of the effects are either--you guessed it--draw or ramp
Lastly, the Voltron can also be let out of the cage temporarily with any of the numerous combat tricks that untap the creature
Back in the old days of Magic (like ten years ago), single card prices were based mostly on their age, availability, and playability