It's kinda weird. HS and college football was almost entirely on Saturday mornings or afternoons. Professional football gravitated toward Sunday to avoid competing with the much more popular college football. With lights, HSs immediately went to Friday night en masse to also get out from under the scope of college football. With lights, at all levels, night games became possible on any night. There were always weird afternoon games throughout the week pre-WWII when teams would go on 'barnstorming tours' and plays several games in one trip.
There's actually a law from 1961 that prohibits the NFL from broadcasting games on Friday and Saturday from the 2nd weekend of September to the 2nd weekend of December, for night games. NFL did the black Friday game last year because it kicked off at 3pm. College football, however, doesn't have any such restriction on playing on days other than Saturday.
Though out of respect for high school football, colleges had almost universally restricted themselves, by their own accord, from Friday games. And college, now much less popular cumulatively compared to the NFL, avoids Sundays when the NFL is playing (kickoff weekend before the NFL season starts has always been a free-for-all).
That's why Thursday always became the 'backup date' for games not on their traditional spot in all three levels. NFL added Monday Night football, which left Tuesday and Wednesday open. Other than bowl season, games just weren't played those days until the MAC got their deal with ESPN. Which, despite the attendances looking pathetic, has been the lifeblood of MAC team building. Easier to recruit when your players come from all over the country and your friends/family/hometown can watch you play every week. Something not possible unless you're at one of the blue bloods of the sport.
I wish NCAA prohibited Friday night games, but the can of worms has already been opened. It's not going back without some type of law, and I seriously doubt in today's political climate anyone could suggest passing a federal ban on Friday night NCAA games. If even one state allows them, you know ESPN/BTN/SECN/ACCN/Fox/CBS, etc would be clamoring for that state to host Friday night games to add another window for live television broadcast viewership.
And with MAC, you're not getting rid of the Tuesday and Wednesday games. And honestly as a football fan, it's nice to just be able to turn on the TV and watch a game throughout the season any day of the week.