It's partially because DOA5U started the shitty DLC practices with the focus around fetish costumes & gravure videos. DOA6 was a lot more blatant with the monetisation bullshit culminating in the Hair Colour scheme in 1.20. Though yes, overall DOA5LR is a fantastic game.
Free Step Dodge
Force_of_Nature
ChaolanLegacy
The big issue outside of the dlc practices is that many players say that "DOA is so bad" even though they haven't played it themselves or haven't gotten deep enough into the game to see what they can truly offer in gameplay that it turns off potential players from trying them out and these days its not easy trying to stand out in a competition where newer and newer fighting games get released
ChaolanLegacy
on a yearly basis now, often ending up suffering in quality because of it. Also, some say that the last DOA4 was the good one because they liked Tecmo (and Itagaki's works) and not KT. Its like how a good couple of people dislike Square Enix and how they adored everything Squaresoft made (rightfully so in a way though, most games post FFX have only been good or quite good