Or stick with a top loader, springs & no heavy concrete...

There needs to be better engineering to dispense with the counterweight.

Top loaders also usually have concrete blocks attached to the bottom of the frame holding the tub and works.
The best way to do it would be to have the filling of the counterweight done by the washer. At the start of each cycle, drain the counterweight into the tub as the first part of the cold water, then refill it before the spin cycle.
Would also need a transport mode to just empty the counterweight and pump it down the drain.

Why can't the machine do this automatically, like have a sensor in the reservoir and if it is empty then the machine will do that on the first cycle. Do top loaders have this weight? They are freaking heavy also, I hate moving washing machines.

@thk .. there is better engineering. It is called a ringer.

"Concrete is actually quite bad for the environment due to the CO2 released when it's produced" - but PLASTIC is good?

Seems like such a obvious idea I'm a little surprised someone hasn't thought of it sooner. Though I do wonder if there is any problem if the water leaks out causing the machine to shake around a lot.

Great idea, stay tuned...

How about using sand instead of water? That is nearer the weight of concrete.

The concrete seems very strange. I have bought exercise equipment in a big city because the small town store couldn't afford the shipping cost of the iron weights.