I think it's the Youtubers who claim how easy it is and make claims of making hundreds of thousands of dollars a year doing it. Somehow those videos made it into my algorithm on YT. Everyday for several months I get at least one usually 3 or 4 pressure washing / house washing videos recommended. I'm sure many other people are also. Seems like there are 2 bigger companies spamming Youtube with how to get in the soft washing business and that birthed a number of people who vlog on yt about how great the business is.
Edit: It also has a low cost of entry to start a pressure washing or soft washing company. From what I've seen you can start one for under $500 in equipment and have seen videos of guys using their cars to haul around the equipment and chemicals. So anyone who wants to can get into the business. On a side note I doubt many of them are licensed or have liability insurance. The risk of property damage is super high when running a pressure washing or soft washing business.