As to why they did not catch on, do you have a little time to talk? First and foremost, the company AVCO that produced the first Bendix Duomatic combination washer-dryer tied up almost everything with patents and intellectual property rights protection. They came up with the idea so anyone who made a combination had to pay them a royalty. Then they patented the construction of the machine with a suspended mechanism that allowed fast spinning for optimum water extraction. No other combination, with the technology available at the time, could have the ability to offer high speed spins via a suspension system to achieve thorough water extraction so the load went into dry with fabrics, especially heavy cottons, with so much water that you could wring it out by hand. There was a prejudice against tumbler washers and low-sudsing detergents they required. The following comments do not apply to the Bendix Duomatic, but it was only one brand and the faults of the other brands poisoned the well for the concept. The machines were complex and were asked to do mechanical tasks for which the technology of the time only offered crude solutions. Seals in some machines, like the Westinghouse combos, were not up to the heat of the dry cycles so they became hard and did not seal the heating element box from water resulting in rusting. Drying cycles were long and in most cases, quite hot and consumed a lot of energy evaporating water that could have been spun out as well as, in the case of condensing drying models, a lot of water; enough to wash another load. The Lady Kenmore gas combo had a 37,000 BTU burner near the floor and the wall of the outer tub. During the drying, the heat from the burner charred the floor under the machine and eventually destroyed the porcelain on the steel tank so that it rusted through. Every machine had its own deficiencies which could have been worked through EXCEPT that manufacturers did not recoup enough money on the original designs to pay for huge modifications, let alone break even on their investment, except for Whirlpool thanks to the number of machines sold by Sears. The redesigned Kenmore machine had over 1600 parts, by count by a brother of John and Jeff, the original combo kings, and was very complex. Service techs did not like the machines because they were big and heavy, usually installed in tight spaces and often required lots of service so they bad mouthed them. Westinghouse offered some of their service techs a free machine if they would keep it running and no one took them up on the offer.
In living quarters where there was not room for a separate washer and dryer, they answered a great need in the days before stacked washer dryer pairs, but I only know of one person who loved her first huge Kenmore combo so much that when it wore out she bought one of the redesigned combos and was sad when she could not replace it with another. She raised a set of twins with the first one.
