The thing is: ONE brand sells a german toploader with suds saver kind thing, but It uses the sotner-rinse-water for the mainwash. That's senseless. The softener reduces the wash performance of the detergent. And it is TL...
So i think on, why don't FL or, especially, washer-dryers use it. Like the washer-dryer using it's last rinse water for the dring-cooling OR the next first rinse. The condensor could be flushed with water as the BSH air condenors do and if it is used for the rinse, the softner-residue could be helpfull on increasing rinse performance while decreasing suds. And the washers would get more stability by the tank in the bottom and they could have enough space if they would build in short-way dampers or use any kind of ropes and pulleys so the downwards forces can be converted into upwards-forces so the dampers are only at the top of the drum. Same could be used with TLs so the sideway-forces would be transfomed into vertical forces so the dampers could work more effective...