Not sure I fully agree. No one is forcing them to carry all these scope lines - they do it because, I assume, covering that many market segments and price points as possible is profitable for them. If Vortex dumped one of their 17 lines of scopes (just counted!), especially on the budget end, I don't think I'd even notice. But they don't do that because stuff like the Crossfire II line is making them money, and introducing people to the brand.
I'd also add that some companies, especially ones selling to .mil and LEO orgs, carry zillions of SKUs because they want their product to be considered a "consumer off the shelf" (COTS) option for contracts. If carrying a ton of SKUs wasn't a profitable strategy, they'd stop doing it. Remember, just having an SKU doesn't mean you have inventory on hand. It's just a number that goes with a product (literally "stock keeping unit").
Nikon pulling out of the scope market isn't good news, but it's important to note that they've been stagnant for years now, and their big new product intro went poorly because, well, it wasn't a particularly innovative scope, and just having the glass is no longer enough. Plenty of people have (relatively) great glass on budget scopes now. Treating them like they're a bellweather for the entire optics industry is perhaps not a solidly-founded theory. The counterpoint to Nikon is Sig, who got into the optics game with genuinely interesting new products, and is now doing well. (Side note, it's funny that we're talking about simple scopes with amazing glass, because there's another thread on here where someone was bemoaning why the Sig Whiskey5 line wasn't living up to its full potential.)
Now, all of that said, I do agree the retailer and consumer confusion when you've got 15-20 brand lines is a real thing. There is a lot of trash to wade through to find those diamonds in the rough at the sub-$500 range, like the Burris RT-6. I like how Bushnell, for example, has pared back on the number of brand lines it's running, and that Nightforce is pretty easy to figure out.