For Bora I guess the issue is that they have Sagan who is a bonafide superstar and Ackermann who is a consistent winner who are both there until the end of next year (that's as long as they have Buchmann for afaik?). Schachmann meanwhile is clearly the long term bet being there another 4 years. There's a lot of one day and sprint talent and assembling a great squad of stage hunters + consistent winners can do you well across a big chunk of the season and net you more positives than having a good GC rider who can be a bit anonymous.
Buchmann's best bet is to get out and win some stages or contest the polka dot jersey now. He was unlucky with the crash and what that did to his prep, but if he's not pulling out he needs to do more than just see the race out.
But the only thing anybody in Germany who's not already a hardcore cycling fan would care about is a Tour podium, best a possible win. Or maybe a Giro win. Schachmann would not be my best bet for that. It's either Buchmann or in the future Kämna or someone entirely else. Even if Schachmann would become world champion nobody would care. And they are very clearly going for the German audience. Apart from a few people hardly cared about Kittel and he has been pretty successful at the Tour.
Buchmann can try something, but I doubt he will win anything in this Tour. He's clearly only hanging on and since he's not punchy how is he going to win any of those stages? Dots would be the only possibility, but even for that he's probably not strong enough now, just as Pinot.
P.S: Among the people I know I am the only one who watches the Tour, not even daring to speak of other races. Maybe I am a bit blind here and there are groups of people in Germany who are different.