And this address is not old, it is veryveryold. How many people mined 2 weeks after Bitcoin was released? I expected that Satoshi had the most mined blocks, so it would be very likely that it is Satoshi. Do you think that this miner sold his address now, 13 years later? And I don't think that Satoshi would sell addresses.
Many people. But most early bitcoiners aren't out shouting from the roofs and courting inviting kidnappers or frivolous legal attacks. Most people with access to very old keys aren't blowing that access on silly Bitcoin talk bragging threads.