The first time I went to Japan (about 15 years ago) I was using a "normal" sized pp, on arrival in Tokyo the agent put the sticker over old stamps not wasting blank pages.
Amazing.
Before GE, US CBP routinely stamped over other stamps, I recollect having 9 stamps on one page.
Also, a ton of stamps on a page can be kinda neat to look at. Feels like "travel done well."