Breh....think about this. There's MILLIONS of videos of YouTube. 1080p, 720p.....full HD.....millions of vids nobody will ever watch/see. Think about all the space that takes up wherever tht stuff is stored.
Now think about some text messages. Just mere bytes of information. Point being, they could store hundreds of years of text messages and not be in danger of running out of space. So Snapchat, texts....you delete it, but it's all being stored somewhere beucase it may be needed in a situation like a murder trial.