Why is Minecraft such a let down?

It's nothing special unless you have a private server with friends and use mods. Vanilla Minecraft is very boring, do the same thing every time. Using mods makes it a completely different game, insane mobs, new worlds, machines, magic and more, using a mod pack such has Resonant Rise allows you to have hundred of mods installed.

About singleplayer, it is only fun if you make it fun. I agree with you, I don't play as much as I did before, primarily because of the community and servers that want to grieve money. About the skins, it's just a chain of children who want to be like eachother. Skin databases usually have these such skins at the top of the popular list, so that's how it adapted to be such an annoyance.

I don't think it's entirely boring. It's great if you're the really creative type. It's virtual lego and takes up far less space than scattering the little bricks all over the floor. I enjoy playing by myself; exploring and building and surviving. It's great with a bunch of friends, too, especially if they're people you game with regularly.

It's not everyone's cup of tea but then again, no game ever is.

Play Terraria.

Honestly, i think it's the gigantic community this game has, you get sick of all the minecraft after a while. Single player creative is the best way to play, even though i don't play often.