for many reasons. lint does not like to travel very far as it becomes clogged soo easy and will cause heat backup. Then any moisture water or whatever will make the lint become paper mache.
I have had customers TELL me that they wanted the lint line sent up in the attic and out an eave vent, but as I have told them lint does not have that much force to travel up hill and will become only clogged at the bend going up. Sure enough it did.
Your only fix I can think of would be to channel the line to the garage then into a box made of screen to trap the lint and to also let the air out with out the lint with it. Many people use the ladies hose method and it works but has to be maintained on a reg basis.
Lets hear what others have to say. This is just not good.