If you go to MBK in Bangkok there are stores selling original DVDs, music CDs,.. etc. DVDs are also available in department store in Siam Paragon. In JB the Popular bookstore there carries music CDs, VCDs, DVDs,.. They also sell them in the Spore stores but only a very limited number when you compare to the Popular store in Malaysia.
In Spore I think the only stores you find in the malls still selling CDs/DVDs is Poh Kim?
So it is not that CDs & DVDs are going out of fashion but rather whether there is enough profit margin to be made in selling them. If you visit Orchard Road the store there are mostly selling branded clothes & accessories with high mark ups. You need the high markup to cover the rentals in Spore.