Because Democrats have turned out to be a total disaster.
Unfortunately, Democrats WIN consistently when pitted against ANY actual Republican.
So apparently the public perception is that Republicans still fall short by even more than the Democrats do.
Democrats are sinking their own ship. Unfortunately, Republicans have a history of sinking themselves even faster and snatching defeat from the jaws of victory.
Some pundit said "Never underestimate a Republican's ability to lose an election."
The Republicans are getting the EXTREMELY rare chance at the opportunity of a lifetime for a SECOND TIME. It is extremely rare for opportunity to knock twice like it is right now.
REPUBLICANS BETTER GET THEIR ACT TOGETHER and get the benefit of this opportunity, or else they will blow it and hand over the win to the Democrats once again.