Morrissey is not a mainstream artist. But in the world of indie/alternative rock, he is one of the biggest icons, if not THE biggest icon.
When it comes to my country, mainstream = turbo folk, r'n'b, dance pop; anyone who listens to rock music and despises folk-pop is not mainstream here. Most of the population (those who are into turbo folk and similar stuff) have certainly never heard of Morrissey. I suppose that there is a certain middle ground - people who listen to hip hop, techno, mainstream rock like RHCP (the most popular rock group according to a recent poll). But in the Serbian 'indie-rock' circles, The Smiths have been one of the most popular bands for decades, if not the most popular, and Morrissey is the number 1 icon (maybe Nick Cave comes close). I know lots of people who adore Morrissey; his songs, solo and with The Smiths, are regularly played in clubs I go to; he is always being discussed on the forums I regularly visit, so much that Moz-haters are always complaining that there is too much talk about him and whining as if they're some kind of oppressed minority.
But, you have to keep in mind that the circles I move in - the few places I go to, the forums I visit, the people I always meet there - are in fact a small minority in this country on the whole. I suppose it's a little world in itself, very different from the mainstream Serbia, but most of the time I have very little contact with mainstream Serbia.