NES, SNES, Gamecube, Gameboy, Gameboy Advance, Nintendo DS, Nintendo 3DS, Sega Genesis, Sega Gamegear, PS1, PS2, Xbox Original...I'd be really interested in when you think this wasn't the case.
Game consoles not being PCs has been a thing for a long time. Even if that wasn't the case it's only in the last couple generations that any consoles have been blatant about the fact that they are just low to mid end PCs.