Guthrie has two options in my opinion...
1) Stay the course with the program, but bite the bullet on the finances and fire Arth, in hopes of the next coach actually turning this program around to a respectable, profitable level. The issue here is: you can't miss again.
2) Become P5 prostitutes. Ditch the MAC, find one P5 school a week to pay you $1M to whoop your butt, tell recruits they'll get to showcase themselves weekly against P5 schools, and get right financially. Play them enough, and you might actually win one or two games here and there, especially with the possible increase in talent if higher-level recruits like the idea of playing against P5 schools. Heck, you could even sell the idea to YouTube or something to get a media deal out of it. Not sure how the contracts work with other conferences, but I'm sure some sort of media outlet would like to show weekly P5 football on their platform.
Dropping the football program altogether isn't an option, dropping to FCS isn't an option, and we can't stay on this path of digging ourselves deeper into debt. Stay the course and get it right, or turn heads and make headlines by adapting to the ever-changing college athletics landscape. Regardless, staying in a state of not being able to make necessary changes for improvement is not a viable option.