The phrase deviyo saha buthayo encapsulates a harmonious cosmology: devas are respected friends, guardians, and sometimes previous relatives, but only the Buddha—and the Dhamma he taught—offers final freedom. As the Dhammapada (verse 188–192) says:
A: Because it is out of print and has limited commercial demand. Your best bet is digital archives or second-hand bookshops in Colombo (e.g., on Chatham Street).