Hear the difference
I love folk music and most of its immediate derivatives: folk rock, roots rock, electric folk. The best I can say about indie is that I can name more examples that I don't dislike than I can for modern pop, modern "rock", and modern "country."
I still dislike the vast majority of indie music for the same reasons I dislike modern pop music (too much instrumentation, too polished, no silence, and the singer always sounds tired) and a few more besides (indie music is more likely to have nonsensical and irritating lyrics, and there's a whole subgenre of "low fi" indie music dedicated to making it sound scratchy).
On the other hand, I've realized that a lot of genres themselves contain sounds nearly as disparate as indie and folk music. It's bad enough that I put "rock" and "country" in quotes when referring to the modern genres in writing, and sneer when referring to them in speaking. In my music tastes, I'm essentially a grumpy old man I pretty much never like music from after I was born; I feel that the eighties and nineties pretty much ruined mainstream music of all genres.
To demonstrate, here are old hit songs I like from the 50s, paired with a song from half a century later nominally in the same genre. In each case, I listened to all the number 1s which had spent at least a month at top spot that year and selected the one I found least objectionable. In every case, I don't feel an immediate dislike for the modern song I chose, but definitely didn't like it either, and stopped listening to each of them less than half way through.
Rock
Country
R+B
Even new acts that I like generally keep the features of older music: they're energetic, relatively unpolished, have simple instrumentation, and generally have periods of silence.
New acts I like
The point is, I came to the conclusion awhile ago that there's generally a far bigger difference between songs in the same "genre" across the decades than there is between "genres" of the same time and place. Now I've finally decided to ask you guys: has anybody else had the same impression?