If the Pollsters were to say Conservatives were Winning, those executives at the Left Wing Media companies would fire those same pollsters and get new ones,instantly,as they only want to feed their Left Wing Audience for TV ratings. ie, "follow the money".
Second, The Left, can not handle the Truth. The Left censor and block Conservatives on Social Media, and shut them out, or shout them down in real life. The same goes for what is happening at the Left Wing Media companies making up stuff, Fake News, about Trump 95% of the time, if not more.
In summary, these Left-Wing Polls (The Magic Mirror) feed the Left Wing Media companies' Narcissism and demand it from The Magic Mirror (Polling Companies).