Nothing that is shall last forever.
D&D in particular is really multiple products created by multiple creative teams that succeeded to varying degrees multiple times relying on brand strength and some degree of underlying strength in the product. It's as if rather than forsaking New Coke, Coca-Cola had continued with it, then replaced it with a succession of Newer Cokes, (X-Treme Coke, Coke Millennium, iCoke, 2 Coke 2 Cola, etc). This sort of business model seems almost certain to fluctuate between highly successful products that retain existing customers while also bringing in new ones, products that get mixed consumer responses, and absolute fiascos. But the point is that a business model that involves abandoning even a flagship product that is still wildly popular in favor of rolling the die on a new similar product branded as a new edition of the same product is an inherently unstable business, and sooner or later it's going to roll a nat 1.
Which is why I think OneD&D is a brilliant business idea in theory, and a terrible one as it is being executed. In its core formulation it is a revision of 5e to make it into a forever edition. This is not realistic (nothing lasts forever) but a narrow, targetted revision of the core product line to make it closer to a forever product and put off a completely new "edition" (ie: replacement product with D&D branding) as long as possible is a move towards a lot better business to be in long-term. However the playtests are not proposing targetted revisions, they are proposing "arbitrarily change just enough to make everyone has to buy a new PHB to play at a 5.5 table, and do it while the customer base is largest" changes. I'm sure this is exciting for the designers, who get to try a lot of cool ideas, and will lead to a larger short term gain in sales of new core books. I'm sure that will work out well for the suits making power point presentations about how OneD&D will integrate product lines and synergize and whatever, who will all have moved on to other positions, if not other companies, by time 5.5 turns out to be a mild flop, which instead of prolonging the 5e line of products hastens its need for further revision or an actual new D&D and all the risks that entails. Basically I think it's a good business move at the core, which is probably going to be executed terribly due to the muddled interests of various individuals in a corporate environment to advance their own careers, pursue their own creative visions, and/or be able to give a good pitch to executives or stockholders.