[2019] Why can't Mirror image copy legendaries ?

Hey.So according to the legend rule :

Only one copy of a given legendary card may be in control by a same player at the same time. If multiple copies of a legend are under control by a same player, the player choose one of them, and all of the rest are put into the graveyard (discard pile).

The cards must have exactly the same name in order to trigger the legend rule.

"THE CARDS MUST BE EXACTLY THE SAME NAME IN ORDER TO TRIGGER THE LEGEND RULE"Unlike Quasiduplicate, which creates a token which is a copy of another creature and takes the name of this creature, once on the board Mirror Image's name remains Mirror Image, hence its name is different than the creature it copies, so why can't it copy legendaries ? I understand that Mirror Image becomes an exact replica of the card, the tooltip does say "This creature is a copy of X", but according to the legend rule, it's the cards names that matters, not what they actually are.

I thought the interraction would have worked like Lazav, which becomes a copy of a creature but keeps its name, so it doesn't trigger the legend rule.