2014: "Democrats' worse case scenario in Colorado is a one-point win. Udall is a stronger candidate than Bennet and 2014 will not be as bad a year for Democrats as 2010. Udall will win."
2015: "Democrats' worse case scenario in Colorado is a two-point loss. Bennet is a stronger candidate than Udall and 2016 will not be as bad a year for Democrats as 2014. Bennet will win."
Nobody said that first one. Everybody acknowledged Gardner was a much stronger candidate than Buck, even though Udall
seemed stronger than Bennet, clearly that wasn't the case. Realistically, could Bennet
possibly run a worse campaign than Udall did, short of having an affair, hiding money in a freezer, or pulling a Casey/Warner and going out to lunch? And while it did seem like 2014 couldn't be as bad as 2010...well, you won't see many Democrats making that mistake again in 2018. Still not comparable to a presidential year, where even if Republicans do well, they'll still have to contend with much higher turnout among Democratic leaning demographics.
Oh, and nobody's saying Bennet will "definitely win" either, just that he's clearly not near the top of the most vulnerable list.