I totally agree with hector the only companies these companies harm are the ones who cater for the same market.
The problem is as carpet cleaners we notice these low prices when we see them, so are constantly aware they exist. Joe Public is 99.9999% of the time totally not interested in carpet cleaning, so these prices are not even registered In their brains .
Often when it comes to getting their carpets cleaned they have no idea these 3 rooms for £60 prices even exist so will accept any price that is presented to them.
Some homes in my area have received over 80 of my leaflets over the years, but until they need my services they never even notice them or if the do they don't remember them. I go to homes who say they got me out of the phone book, when ask if they have seen my leaflet they say no.