Kobel wouldn't be really that much of an upgrade and I think they need to start thinking about the future. Neuer might be injured now and can come back eventually but that doesn't mean that when he comes back he will be all that amazing, he is already getting old. I would guess that if they could find some 20-23 year old goalkeeper that is amazing and could be good for them, it would be a smart decision to make.
There aren't all that many goalkeepers in the world under 23 that worths that much money or show that much promise in the future, it is a bad period and they definitely need to replace Neuer soon so it is going to take a while and they might get too late. They should start the scouting process very quickly and find someone. You can't tell me a single good under 23 German goalkeeper right now, that is an issue for them. This means that it is going to be very tough, and losing time with players like Kobel would only make it even worse for them.
Neuer is very old now and that's why I think he won't be able to play like before even if he recovers from his injury. Goalkeepers can play for longer years than other football players, but their reflexes slow down and they cannot play as well as they used to. Currently, there are goalkeepers among the young goalkeepers who we can say are very good, but I am not sure whether they deserve the money paid to transfer them. I think the current goalkeepers are not playing well according to their value
Of course there is difference between Manuel Neuer and other goalkeepers who are also quite old because Neuer still has the speed and agility that can compete with other young goalkeepers especially the two goalkeepers currently owned by Bayern Munich.
He will play one or two more seasons with Bayern Munich before actually leaving and retiring so there will be big surprise or you could say gift for Bayern Munich which he has defended with all his greatness.
But if you evaluate the goalkeeper currently used by Bayern Munich namely Sven Ulreich who is the main goalkeeper actually he is not that bad and can still be said to be great goalkeeper look at him he only has a history of conceding few goals while playing with Bayern Munich this season.
Even though the price and salary are quite large it is still comparable to what he gave for Bayern Munich.