This meme is bad because it forgets Pokemon games released from 2013 to 2021. Unless they're implying that recent games aren't largely linear.

The Coronet Highlands in PLA is one of the best designed areas in any Pokemon game. Period.

It actually is a "Series of Interconnected Routes" and not a linear hallway that happens to loop back on itself like most Pokemon games. The verticality of the area also plays very well of the various ride Pokémon's abilities, which are useful for both travelling uphill and downhill.

Only parts of the game that felt "empty" enough to even vaguely represent this meme is the tutorial area that's cut off from the rest of the Obsidian Fieldlands and the central area of the Alabaster Icelands.