Capcom took a while to learn to count past 2.
Yes, and Final Fantasy seems to never actually be final...
The question wasn't "What will some marketing hack call it?" It was, What should WE call it?
I submit to you that given that gamers can, for the most part, count to ten without resorting to using fingers that 5e is pretty much the inevitable construction.
Yes, a major product line can change its system (Windows 98), but D&D is, on those terms, small potatoes. I don't expect so much as a single nationwide TV ad campaign - WotC doesn't have the oomph to override the customer's tendency to name things as they wish.