Very few people actually change their SSID. The bigger point is that, considering sites like Wigle.net exist and the Google Street view cars were designed to capture all SSID data (they hired the guy who made NetStumbler, a popular open source SSID scanning tool in the early 2000’s), it’s trivial to get within a few hundred feet with just a few SSID’s in an area. When your neighbor has an SSID of Comcast-12345 (aka random string), there is probably only one location that has your SSID and the Comcast one in the same location. You can change your SSID every day, but your neighbors probably don’t change theirs.