I 100% can see it easily selling for that much.
You want to know why it's worth that much?
Petabytes of raw training Data for LLMs. Arguably atm reddit us one of the better gold mines of LLM training data on the internet, bazillion of posts already formatted as post-response chains, which is the exact type if format an LLM wants to train on.
Can you imagine how valuable those servers loaded with posts are to a company like OpenAI, Google, or Microsoft?
5 billion is quite reasonable to harvest every reddit post that has ever been made ever and cut it off from your competitors.