Besides the cost like another comment mentioned, the album is a dying format. Not to say it won't stick around to some extent , it's just not as popular as it once was.

Singles are the way of the present. Why?

• It costs a fraction of the time and effort compared to a whole album
• there is so much more competition for listener attention than ever before that putting out more than song dilutes the chance of a listener hearing the best work
• the average listener isn't listening to whole albums, especially from a new artist they don't know of
• getting onto a playlist is one of the bigger ways to get noticed, and no big playlists are adding anything other than single songs
• for a band or artist that is actively trying to get noticed, there is a lot of effort that can go into advertising and marketing. Promoting one song, one music video for that song, one remix of that song etc. is a lot of work already and arguably more effective than promoting multiple songs. Think brand recognition.
• they could be "saving" unreleased songs for a time when they are ready to release an album or EP, or they could be testing the waters to see if live crowds are into it before committing to a release or not

That's just my thoughts and opinion on the subject as hobbyist music maker, seeing what people are doing these days. I myself prefer albums and will listen all the way through, but it's no longer the standard.