I'm assuming you have functional eyes and saw how these two looked on the same field in B&G game.
Buchner is not on Hartman's level any more than Hartman is on (name an elite QB) level.
The mistake you and so many have made is comparing what Hartman did this year to what they did last year. Three things make this a flawed comparison: OC, OL and Mayer.
Buchner and Pyne would have struggled mightily this year, with Parker, OL that consistently got beat quickly and badly inside putting DL right in QB (Pyne) face who was not mobile enough to escape and WRs who didn't create much separation most of the season forcing QB (Buchner) to be highly accurate which he wasn't.
This season sucked with Hartman and I'm disappointed, but it didn't suck because of him, he just wasn't good enough overcome our obstacles consistently. But if we had Buchner and Pyne, this season would have been a total disaster.