I think it is partly sour grapes and partly denial. McConnell is part of the RNC establishment that feels at home being the minority party.
Trump won based primarily on two issues: Immigration and he responded forcefully to Dem mud slinging, refusing to grant them control of the discussion. I may not be a fan of Trump’s Tweets, but it will take a lot more than sloppy facts and worse spelling to make me tun my back on him. If his tweets are part of his being a fighter, so be it.
His tweets allow him to completely bypass the professional liars.