All of these points are certainly contributing factors -- after such a long time of essentially being closed to foreigners due to COVID tourism in Japan has exploded and is reaching pre-pandemic levels -- Ginza on the weekends starting this spring was scary -- now it is truly terrifying. It is great to see the city recovering -- but wow it is so busy now and I believe there is a lot of competition for hotel rooms. My wife's parents are coming to visit in a few weeks and staying at the Dormy Inn near us -- which has doubled in price from the last time they stayed last year.

OP one thing I would add is that unlike many other markets in Japan rates hardly ever go down the closer you get to the date -- even if there are a lot of free rooms - they typicially go up. The airlines work the same way. If you find a good deal I would recommend you lock it in...