How many whales are there in the world? That are willing to spend insane amounts of money for internet points and colourful pixels?
On-topic, if D4 has the cool aspects of all of its predecessors w/o their shortcomins it will be a smash. If at the same times d4 has the good things that Lost Ark has, (combat & especially the dodge mechanic, bosses-dungeons-pvp) it will be a huge hit. But if on the other hand has all these and on top of that has some obscure monetization practices it will surely sell good but it will never capture the hearts of the masses apart from those whales.