Wifi WAS extremely scarce in Japan. When I lived there a few years ago the phone plans were great for me but it was very difficult for friends visiting to have internet even in Tokyo. When I was there last year there seemed to have been a pretty big push in preparation for the Olympics, most stations did not have WiFi in 2015 when I moved away as an example
If by “a few” you mean more than 5 then maybe. Free WiFi in all convenience stores, most train stations (almost all in bigger cities Tokyo, around half in bumfuck countryside where I live), many major public spots and department stores, expressway buses, and many cafes and restaurants all have free WiFi.
I was without a SIM card for several months recently and rarely had to go far finding connectivity.
Train stations, 7-11, Family Mart, Starbucks, Gasuto, McD's.
Plus all of the locations in the Japan Connected-free wifi app.