I dont for one minute think it'll influence how many window cleaners there are out there; and never have despite the bleatings of some on here about it. Its a big population, why worry if it does? If it did and lets say 100 new shiners decided to take up window-cleaning as a trade after reading earnings threads on here the figures would go something like this:
100 new shiners multiplied by 300 houses on their books which equals 30,000 houses. That's forgetting all the other stuff about what they could do, such as shops, offices, retail outlets bla bla bla. There's about 25 million properties in the UK. That means that the 30,000 properties the 100 new cleaners were to take would mean there were only 24,970,000 left for the rest of us.
Or put another way they would have one house in every 833, which is about one house for every 3 window cleaning rounds.
Never worried that the discussion of earnings on here is likely to affect the business as a whole. its a forum with a few members, we're not that important nor are we particularly well attended by any one thing that is likely to influence our working practises.