Sherco
You're probably right, but the skill required to clean carpets is minimal, compared to tiling or any building, or other trades.................we're talking about practical skills here, not working out with accuracy, levels, measurements, maths, all of which are necessary in leaning trades.
The operation of removing soiling from fibres and textiles is minimal compared to anything involved in general trades.
Sure, if you want to use exactly the right product ( as claimed by manufacturers ) you need some additional guidance, but again, you could just read the label !
You will be blinded by science, or the apparently essential products for specific jobs, or you can find a couple of products which will stand you in good stead, 99% of the time .
If you want to show off to clients by displaying a van with racks full of stuff you'll never use and which cost a considerable sum, you can fill your van, but you will only impress yourself, weigh down the van and lighten your pocket.
As a tiler do you survey a job, assemble the essential products with a little extra and take what you need to that job, or do you fill your van with sand, mortar mix, bonding, expanding filler, grout, skrim cloth, brushes, etc, just in case.
An experienced tradesman / craftsman / engineer / whatever, can attain a result with a basic kit of items / products which they have learned to get the maximum return from, carpet cleaning is the same.
But, as you say, with my thinking, I should probably never been cleaning carpets and upholstery for the past twenty four years, but why do people keep phoning me and giving my number out to their friends and relatives..................
Cleaning carpets can be hard physically, but it hardly stimulates the brain cells.
rob
