I think the reason that was removed was that roon started adding other sections at that time and as it was all getting a bit cluttered so something had to go. That might have made some sense with some genres where Production was a specialist engineering interest with collectors. But with genres where Production is where roon has categorized all the creative roles, the effect has been to render roon almost unnavigable for those users. Periodically, this keeps on being pointed out.
Unfortunately, the tricks being described in this thread are not really a solution as it is just too much manual work for anyone with a sizable Electronic library. However, it may help to improve the navigability of some favorite artists on a case by case basis. What is really needed is for roon to address more systematically the way in which it treats presently categorised production roles across all genres.