Indeed, but even in the first Bajor episode (TNG Ensign Ro) it is metioned that no one wants to integrate the Bajorians...
As for time of refugee camps, it exists also since it one of the longest post 1945 occupations. The Saharawi people and some family from the partition of India also have multi-generational refugee camps. and some of the african camps are getting to be multi-generational. Normally the political issue is solved before it gets to the point of say, the 1967 camps.
you mention a long-term occupation, but what was stopping them from integrating refugees into the West Bank, which Jordan had de facto if not de jure sovereignty over from '49 to '67, or the West Bank or Gaza from the Oslo Accords era ?
if you mean Israel itself as a long-term occupation, well it's not exactly feasible that they're going to integrate the refugees there.