5000 BTC from Satoshi-Era Wallet Moved, maybe 3 More Wallets Wait to Send Bitcoin as they have the same origin ~21000 BTC.
It's strange that they didn't have any movement when BTC was over 50k...

No it's not strange at all. You move your coins when you move your coins. A few reasons why people move coins are:
Wallet software or hardware change
Death. Coins were recovered by family and moved.
If it's a Mt.Gox wallet these are being redistributed this year.
We could go on and come up with a few more but what's the point? As it was said earlier in the thread moving doesn't mean selling.
People are just too reactive when it comes to these kind of aspect which it isnt really out business on whether those coins would be moved or not by its owners.