I have 4 dcs 10 and under, dh and I. One dishwasher, one washing machine (7kg). We manage fine. I do 3 dishwasher loads per day (4dc packed lunch I'm a sahm and dh works from home. Thing is, when I've stacked the dishwasher, I still have more dishes in the sink! I could see the benefit of another slimline dishwasher or a drawer dishwasher.
I can cope with the washing machine. 1-3 loads a day. More if I do sheets and towels, but I'm a bit of a slattern. We have one Lakeland heated rail, one more would be helpful.
We don't have a huge fridge, but we may get 2xsmaller Ocado deliveries to manage this.
2 x is only something I've ever seen on larger family forums.