In New Hampshire Biden wasn’t even on the ballot and won handily by write in against his primary opponents. I’ve only heard that there are 3 states in which Biden is the only candidate - and that’s because other candidates didn’t qualify.
Also, I’ve not seen any fantastic primary contenders step forward anyway. What makes you think Biden is “historically unpopular” enough to be the incumbent and be voted out in the primary?
Oh absolutely. I always pay attention to who I’m voting for and what I’m voting for.