There is a natural tendency in all things towards bloat. Bureaucracies expand inexorably as their members annex ever-greater levels of control. Wealth accrues to the wealthy through interest and investment. As you age your body expands and you have to work harder and harder to fight its natural tendency to resemble Jabba the Hutt. And as sure as eggs are eggs, a new edition of D&D, sooner or later, starts to bulge at the seams with new rules, new classes, new books. Like Japanese knotweed, the process cannot be stopped once it is underway - at least, not without a heck of a lot of toxic chemicals and large-scale mechanised excavation.
I like 5th edition. It works well. But the knotweed is already on the march. There are gaps that must be filled! There are gaps that must be created in order to subsequently be filled! There are genuine needs! The logic of D&D bloat begins in earnest with these observations: it is only a matter of time, you must be acutely aware, before they are trying to sell us books about the anatomy of illithids for £12.99 and yet another Dungeoneer's Survival Guide.
Fair enough: I'm not the target audience for these things, and companies have to generate revenue in order to survive. I can't help but feel, however, that since this sort of thing has been going on since the mid-80s with what could charitably be described as "mixed success", it could be time to think of a better long-term strategy than: let's just get people to buy more and more rules.