Excellent point, and I agree, though the vast, vast majority of the pushback I feel I get when advocating for these kinds of shifts are from wealthy/healthy individuals.
It's a classic tragedy of the commons scenario: existing resources should be able to support our current level of creature comforts with minor conservation, even if a segment of the population is less able to support the conservation efforts, but the extremes people demand in turn place extreme load on our infrastructure.
That is exactly the people reducing expenses even when they know that will be extremely painful. That is why the poor are poor, because they cannot afford that kind basic expense. They need to choose between heating and food.
"Let's consume more" for the poor. It is a grotesque argument.
OP was making a fair point that not everybody has the same amount of time and energy (or money) to tolerate shifts in their routine, which in the context of a "personal vs collective responsibility" style argument is entirely reasonable.
By the same token, if only the _rich_ have the freedom to make such behavior changes for the sake of conservation it will only ever have a token impact, and in many cases the "correct" level to make an efficiency pitch at is the community: a decent light rail system will always outperform everyone driving their own vehicle to work/the store/downtown in terms of space and energy efficiency.
...but, to get people to buy into such "collectivist" systems, you often have to get them to contend with some perceived reduction in personal convenience: yes, a train doesn't need a parking lot and uses less gas per passenger-mile, but then you're beholden to the train schedule. It's exactly _that_ sentiment that I find frustrating in advocating for sustainable civic design.
To OP's point: whatever that "collectivist" option is necessarily has to contend that standards of accessibility and convenience are not constant across the population. That doesn't inherently mean "the poor should consume more," but that "hang dry your laundry" isn't an option for everyone in the current dominant socioeconomic structure.
Most of us don't. But smart meters are free in the UK, and if there was a way for my washing machine to have a 3h window overnight to run in to be done for 7:30 I'd do it in a heartbeat. Same for my dishwasher. Heating is a bigger issue.
I think most of these appliances sold today have at least some sort of "delay start" function. We use that to do exactly what you describe. Not even for nght tariff, it's just convenient to time it like that.
There should be plenty of opportunity to load shift with other things though, a dishwasher as you mentioned, or a fridge or a storage heater or a charger for your electric car. All can be done with minimal inconvenience to the user.
Rinse hold solves this. Even the cheapest machines have it.