Yeah it takes more time than you think >>4364912
. Art assets for every tile, character, environmental object, enemy, item. Along with animations for every attack, movement and ability. Animations for each of previous but for every item that can be seen when equipped. And if you want the pixel art to be good, you'll have to go through and do all the clean up with shapes, borders and AA for each frame of each animation. And that is just the art.
Lots of programming, balancing, sound and world design. I'm sure I'm forgetting a fair bit but even after all that you've gotta market the thing and have people actually be interested but if someone else is working on this then what makes yours better?