First, we should be talking about the next 20 years - after all we are talking about a law we will introduce today, not in the past, and noone it talking about appliances lasting a century.

Secondly, while I never used a top loader, from everything I've read, they are worse in every dimention, so the comparison seems inappropriate - you are introducing extra variables.

Also I am not clear why 'incrementally adding water' was not possible previously, People built a 'smart' toaster 70 years ago, that could sence how cooked your bread is, and it was purely mechanical:

https://www.theverge.com/22801890/sunbeam-radiant-control-to...

Top loaders are basically an automated version of doing laundry but by hand. A 40-50 year old top loader which is probably what mine would have been today if it had kept working is much much simpler in many respects than a modern front loader. The spin cycle and it’s control is very different. I doubt you could build a modern washing machine with 1970 technology even if you knew what the end goal should be. And you need the right detergent too.

Added: And toasters still do a crap job of figuring out done-ness.