If you remember Smurf, when steam floor mops first came out they were all the rave because of clever marketing then many other companies jumped on the scene with their own version of a gimmicky cleaning tool.
It will be the same with window vacs one company introduces it to the market now already there are many other versions available for another gimmicky cleaning tool, but that is down to the power of good marketing campaigns.
Just to share the way i see it anyway, and i have been around long enough in this game not to be taken in by clever marketing campaigns. Tadgh