Larger countries with, AFAIK, no ´real´ lower advance tickets/fares, are mostly Eastern-Europe, probably heritage of the past. Hungary, Slovenija, the 3 baltics; Lithuania/Latvia/Eestti=Estonia spring in my mind. From what I recall the cheaper/lower advance tickets they do offer are for INTernational. So there might be the odd case where such a ticket would come out a few cents cheaper as a domestic fare for a longer run. But this may well have been introduced since I did my last search-years ago by now.
Also here in ASEAN its the norm: Thailand, Malaysia, Laos, Cambodia do not offer them. BUT there is for some populair routes/seasons in higher demand another catch: such tickets in the classes in higher demand (yes, 1st cl. sleepers) are snapped up by agencies as soon as released/open for sale who then sell them onward to customers in the know at an added premium. But all the time I visit THailand-by now well over 33 years, the basic 3d cl. regional fares have not been raised. But the various supplements for express/sleeper etc. have been. In that time basic BMTA Bangkok citybuses fares have gone up from then 2 to now 8 THB. Some other mostly aimed at locals state-set prices are also stable all that time, like some specific postage stamps.
I think advance fares for domestic journeys in Switzerland are a fairly recent introduction.