I think a lot of you guys are confusing fantastic art direction for amazing graphics. There really isn't anything special about Wind Waker HD. It has fantastic art direction, which is why it can look good even today. Okami and Beyond Good & Evil are similar games. But its completely ridiculous to compare a Gamecube game to a current gen console.
And you're confusing
amazing graphics with photo-realistic art design. The descriptor,
amazing, is just that - an opinion. It's just as if saying Wind Waker has fantastic art direction, too.
And yes, there are games on GameCube when played on the appropriate television set (a 480i/p standard CRT) that look just as great as PS4/Xbox One/Wii U games. Rogue Leader, Wind Waker, Resident Evil 4, Soul Calibur II, Star Fox Adventures (ridiculous fur effects), Pikmin, F-Zero GX, and even Beyond Good & Evil.
Art style or photo-realism..or not, appropriate to its original resolution and viewed on its respective display, yes, these GC games look just as good as the games' and their respective screenshots you posted (look, I can opinion, too!)