This may be part of the reason:
“Tester had received $19,227,650 in campaign donations and spent $17,674,961 while the Rosendale campaign had received only $4,722,943 in campaign donations and spent $4,204,778.
Tester also had a drastic advantage in PAC support, with $3.6 million compared to $325K for Rosendale.“
Rosendale was VASTLY outspent by Tester. Not to mention the power of incumbency.
So do we know who won Montana and arizona Senate yet?