which shows how people who were struggling to reach 1BTC target are succeeding these days and are even surpassing that target heading to the next one.
This is not what it shows. This image shows the number of
addresses that have a balance greater than 1 BTC. This, by no means, should be translated to "people who now own > 1 BTC". Someone with 20 BTC can spare it in 10 different addresses and create 10 new UTXOs of 2 BTC each, but the owners of > 1 BTC will remain the same. Moving coins doesn't necessarily mean they're getting sold. Furthermore, coins that are sold, don't have to be necessarily moved into one address.