The Internet in 50 years will not be anything we can imagine. Remember back in the '90s when the Internet just started being available to consumers? If you were then to look at the Internet of today it would be a mystery wrapped in an enigma. This is very likely to continue being the pattern.
Horcon is right about just archiving data locally. It is cheaper in the long run, and you never have to worry about anyone or anything mishandling it. So long as you treat it well, it will endure decades or more.
Be wary of optical discs though. The dye used in them seems to degrade over time until only a very small number of drives can read them. (Usually the same model that burned them.)
Depending on how much data you need stored, there are different ways that each offer advantages and disadvantages. If you intend to store your media in a place that is not shielded from magnetism, or may occasionally have high humidity, an SSD is a more reliable data storage device than a mechanical hard drive.
If it is a very small amount of data you need stored, trust redundant copies on USB flash drives. They are dirt cheap and can be stored in conditions that would destroy any other media besides SSDs. (Since SSDs are flash memory too.)
The first time I bought a flash drive someone asked me how I knew it would be reliable. I responded by tossing it into my cup of Coffee. I then explained that other than the contact points on the USB port, it was not only entirely waterproof, but also could not be broken by mechanical mishandling. (I.E. being dropped or thrown.)