I started in the late 60's and commercial companies were already using them.
Scot Young (of SYR) had the original contract to sell squeegees in the UK, but couldn't get the British Shiner to accept them.
He hired a taxi for a week, drove around London and every time he saw a shiner polishing a window, he leapt out with his bucket, swabbed the glass, squeegeed it and jumped back into his taxi and drove off.
Within the week the story of the ~"Phantom Window Cleaner" was all over London, shiners were demanding to know where they could get this "magic stick", and Scot Young's name (and fortune - he's a multi-millionnaire) was made.
It's the same story now - WFP has been around for years, but it's only in the last few years that it's becoming widely used.