Volume drop = those that were mining are selling the NXT since they are making less profits, while those that hold big bags (the early guys) will make more then.
Mining? I will give you the benefit of the doubt and assume you are aware that NxT is PoS and uses the term forging and you are attempting to make a distinction between the 20-73 initial investors and "btc miners" that invested in later and are now dumping their coins.
This is an odd bit of reasoning as it assumes that secondary investors were able to purchase up enough coins from initial ones to be able to continuously dump them for extended period of time(over a year) to insure that the coin capitulated regardless of new adoption. Even if you were to make this unusual assumption who cares which group of investors are dumping as the bottom line is that there is continuous long term dumping occurring here and not short term manipulation.
So either NxT has practically no new adoption and early investors are slowly dumping or NxT has steady adoption and the early investors are dumping heavily. There is no escaping this fact.
The early guys have no incentive to sell if they held for so long, they can make 1000$ from mining if they hold a bag big enough.
Being that almost no merchant accepts NXT and those that do indirectly quickly dump them for BTC and Fiat the coins eventually are getting sold for other currencies ... even the forging interest.
NXT is obsolete tech from the stone age of crypto. The platforms of choice this year are ETH, rootstock.io, Bitshares, and others.
Is there anything that backs your words?
I agree with CfB ... do you have any evidence to support this statement? I personally don't see NxT as obsolete tech (But neither do I make the assumption that it represents cutting edge "Crypto 2.0" either as those are just marketing buzzwords)