Many spot removers have a time element involved
Your shower logic's flaw misses the time element:
The problem is there is NO quick shower right away in the washer like if one had an eye emergency and used an eye shower.
It is more like getting some bug spray in one's eyes and walking outside looking up in a fog, mist, or drizzle "HOPING" with time after 15 to 20 minutes one has a few drops in ones eyes to clean out the poison.
There is NO big shower, more like some whussy mini sprays every now and gobs of drum revolving such that a random shirt is full wet in 10 to 30 minutes, depending on luck. Thus treated spots bleed, dry, tend to set.
What I mean is that if one stops the wash cycle after 15 minutes and has 8 shirts; some are still bone dry; most are damp. The water level of the tub is below the basket. To save water, there is just wimpy sprays and random motion of the basket. Calling it a shower is a stretch, it is more like a spray of window cleaner a few times per minute. That is why the wash cycle is so long. There is no bath, no shower, ie just a mess of wimpy sprays like one is cleaning a monitor.
Thus here in the USA most of the grease spot removers like Shout, Spray in wash say to spot then wait 2 to 5 minutes; then wash immediately.
It just means that after 10 or 15 minutes if unlucky; that spot that was sprayed is still bone dry and the spot remover's effectiveness is ruined. ON the spot has lifted and now dried on the other part of the shirt. It means one has to rewash ones clothes again to get the spots out.
Thus here some shirts have this white spot where the oxidizer bleached the shirt too much; others have shirts that the spots did not come out all the way. ie a drop in performance to met the government specs.
****Pressing the "extra water button" means the clothes tend to get wetting quicker; since some are in contact with actual water in a tub.
If a lady dyes their hair and it has to be washed out in 5 minutes to get the color correct; it is washed in a tub of water or good shower in 5 minute; not a few wimpy hand sprays a few times each minute such that after 15 minutes one still has not contacted all the hair surfaces.
Maybe clothes in Europe are free and water costs more than inkjet ink.?
Here clothes have a cost, and pressing the "extra water button" or hacking into the washer's guts will be done to allow water to properly get to clothes in a timely basis to reduce spots on clothes.
Many spot removers have a time element involved. It is a process issue.
Thus the lay inexperienced designers have created a machine that saves more water; but fails in 1910 technology in the basics of stain setting; ie not letting a stain set by farting around getting water in contact with the stain in a timely matter. A housewife in 1910 understood this, the lame government spec writers today and designers do not.
If you really want to feel bad, my grandmothers washer In Detroit was water powered. There was no electric motor. The water pressure ran through a "water motor" that moved the clothes. These were made by Coffield in Dayton Ohio.
A COFFIELD POWER WASHER.
It was not until 1978 here until the house even had a water meter. Think of it like the internet, where most today have no data limits.
Maybe in a few years usage of data will be frowned on and every house is taxed 5 bucks per gig of data?
