People will complain about anything, including not getting enough free things for doing things they were already doing anyway.
"I got 400 million credits and all I got was 400 million credits!"
People talking about "losing" ARX are utterly ridiculous. You're playing a video game, the same as you did before ARX, but you're unhappy because you don't get as much as a bonus as you want to get.
But there's no limit. There is never going to be "enough" to satisfy people who are determined to expect the game to suit them specifically, and nobody else. If the cap was 800 per week, there would be more threads about how hard it is to hit the cap. If the cap was 200, people would complain that they don't get enough each week. If the cap was 1000, people would still complain they don't get enough each week and it's too hard to hit the cap.
Let's be perfectly honest about this thread, if you were aiming to get ARX you wouldn't be bulk mining. ARX rewards are greater for less profitable activities. If you're worried about ARX enough to complain into a thread but not worried enough to do literally any activity that easily rewards them, the problem is personal, not systematic.