There are 4 differences between my home and that of my grandparents from one century ago, which indeed have reduced significantly the time spent with household chores:
1. Washing machine
2. Vacuum cleaner
3. Microwave oven
4. Electric refrigerator (but they had a cold underground cellar, while I no longer have such luxuries)
There are also various modern tools that are not used in the normal day-to-day life, but only when incidents happen, which require repairs, for example an electric drill or reciprocating saw, or a soldering iron, or an electric sewing machine (but my grandparents had a mechanical Singer sewing machine, which did the same job, only with more effort) and sometimes, but not often, I prepare some kind of food for which an electric mixer accelerates enough the preparation to compensate for the time spent with assembling, disassembling and washing the mixer.
While other modern inventions, like computers, are very important to me, none of them has reduced the amount of work that must be done in my home (I never felt the need for an automatic dishwasher, because I never let them accumulate, I wash them instantly after use, even while cooking, because I eat only food that I cook myself from raw ingredients).
The mechanical sewing machine would definitely be on the same kind of list, if you had asked your grandparents to prepare one.
> (I never felt the need for an automatic dishwasher, because I never let them accumulate, I wash them instantly after use, even while cooking, because I eat only food that I cook myself from raw ingredients).
Batching usually lowers the total amount of work you have to do. In any case, the dishwasher becomes more useful (for most people) as the household gets larger.
I find that when we cook and bake, we need the dishwasher more. If you only eat out or eat take-away, there's barely any washing up to do.
I thought of a fourth modern machine for your list: the elevator. But it only applies for some people.