Correct. I'm one of these long term players (and spenders) who quit many months ago, and know of many others who have also left. It used to be manageable, but with every new world release more and more new mechanics cannot even be considered usable without using paid currency to upgrade them, and the income from the game makes those upgrades take an unbelievable amount of time. Also, the outright switch to gacha mechanics for some things, especially during time limited events, put even more pressure on players to spend money. That and the shift to more active gameplay, where you let your character actually be online and actively killing stuff, rather than the IDLE of the title has become progressively more and more irritating.
Add to that the fact the developer is an outright sociopath who's incapable of taking ANY criticism, to the point he was joining the Discord servers of the game's guilds to spy on what they're saying about him, and that he banned people from the game before for leaving negative reviews on the game's storeftonts?...
Yeah. Do yourself the favor and never play this.

The reviews on that game from long term players indicate it has pivoted to move predatory mechanics to encourage players to dump more real world currency into it.