I agree, writing games using simple sprites is much easier (especially if you are like me can't draw very well).
I played a lot of 2D games with simple graphics when I was younger (I'm 35 now) and the games were just as fun as games today. In many ways games have not developed much besides the graphics getting more realistic. But the success of Minecraft, Angry birds, threes, crossy road, flappy bird, monument valley and vvvvvv show that good graphics are not required for a popular and fun game.
Good luck with your games, you obviously work much harder on your games than I do right now and I hope you make that game that makes a million downloads soon so you can go full time as an indie developer (or you make the next minecraft and get bought by Microsoft for $2.5 billion!!!!)