In Michigan, having your turn signal on does NOT give you the right of way.
Right of Way? Who's talking about a right of way? lol. All driving is give and take. I almost always let folks in on the highway that are casually trying change lanes to pass. The exception is the dirt spit A-hole that is weaving in and out, passing on the left and being rude to other drivers. For motorists that are driving normally, I will always make room, even truck drivers. If I have been working to change lanes and had my blinker on for a while, I expect someone to extend the courtesy for me. If not, I tend to make my own space and then politely thank them for "letting" me in.