I guess all politics stories in a tech site are going to be misinformed flame wars one way or another, but the amount of people here shitting on the media for manufacturing close-races and going on about how polls have nothing to do with democracy is shocking.
Let me introduce you to the Median Voter Theorem. Which formalizes how the candidate aligned closest to the middle, policy-wise, always gets the most votes (because he is closest to more voters than other candidates). Though MVT is a proof in one dimension, and of course real-life politics deals with many issues and dimensions, it is also obvious that, on the aggregate, the candidate closest to this central policy-median will attract the most votes.
All of this is simple stuff that anyone that TALKS about politics - certainly FiveThirtyEight and cohorts - take as a given. This is also simple stuff for people who DO politics, and for people who INVEST millions of dollars in candidates. So why, do you imagine, in any working democracy - where public opinion can be accurate/legitimate - would anyone simply DECIDE TO LOSE ON PURPOSE by taking a stupid, verifiably unpopular position?
Anwer: NO ONE DOES THAT. People run also-ran campaigns on fringe platforms to influence their party, get attention and a cabinet position, grift campaign donations, whatever. But in the general election, the actual election, everyone does their very best to sit at the very middle of their constituency, the spot that appeases most people, because they WANT TO WIN. Note that 'their constituency' may ignore rejection-voters. Like, I don't think the family of that dead Capitol cop is going to vote for Trump, whatever his new position, so moving towards them is a net-loss. Anyway, nation-wide, these disjoint fixed-constituencies offset positions a little, party-wise, and the final platform bids end up not-identical. But VERY SIMILAR.
Not because it is a media conspiracy. Because that is the whole point of REPRESENTATIVE democracy. You try to represent as many people as possible. And the way to do that is by asking people what they think.: i.e. polling. And the result of that is EXTREMELY CLOSE RACES. Obviously.