I don't think anything necessarily "happened" to Vortex that wasn't already happening when they first hit it big in the optics industry. They haven't really changed anything, same marketing campaigns and same business models. The difference is everyone else and their dog is offering "high value," "bang-for-the-buck," "good for the money," type options now. Even the mighty Gold Ring has fallen flat on its face. Vortex was the first, true, working man's optics brand in the 21st century. They marketed better than companies like Leupold, adopted new scope tech (functional or not) before companies like Leupold, and they pioneered the warranty game to what it is today (yes, I know Leupold had a lifetime warranty before Vortex, but their performance on warranty claims paled in comparison to what Vortex rolled out, and still does).
The thing is, now everybody and their dog is offering comparable products. So now they just kind of get swallowed up in the noise and the product offerings. Seems like everyday there's a new mousetrap, with companies like Athlon offering similar products at similar price points. Case in point with the Athlon, before my adoption of the SWFA's on my hunting rifles, I decided to pick up an Ares BTR Gen 2. I called up Athlon and asked them point blank what this optic offered and what type of performance I could expect for the +/- $1k it was going to cost me. Their response: "Have you ever handled a Viper PST Gen II? If you have, it's basically the same." They didn't offer me any specs from their own mouths, they didn't say anything positive about their products to try to differentiate it in any way. They literally just told me I was buying a PST Gen II equivalent and that if I was happy with a PST Gen II, I would be happy with an Ares BTR Gen 2. That's the type of stranglehold Vortex has on the mid-range optics industry, and that's from the view of their competition.
Point is, I don't think Vortex is doing anything that they haven't been doing since their inception. I just think everybody is using the same sauce and marketing it as something different. The perceived value in today's market is gone because lots of companies are trying to do the same thing. The real test will be when we slip into a recession. My guess is Vortex will survive, but some of their direct competitors (like Athlon) may not, simply because at the end of the day, Vortex has more brand recognition. This is all speculation, of course, but it will be interesting to see.
I think another mistake people make when looking at Vortex is comparing it against the wrong market. They have some high end offerings (Razor UHD Binos, Fury AB Binos, etc.), but most of their stuff is pretty middle-of-the-road. I think that, because they were so popular for such a long time after they first hit the market, people kind of forgot the type of company they are. They're not trying to compete with Swaro and Leica and Zeiss, but people compared them as a "relative value" proposition to those brands, and still do to some extent. But people should be comparing them to Leupold, Nikon, Sig, Athlon, even Bushnell in some pricing tiers. And IMO, Vortex blows most offerings from those companies out of the water without even breaking a sweat.
We just have so stinkin' many options on the market now, and it seems like there's a new direct-to-consumer, high value, bang-for-the-buck optics company popping up every day. Vortex has held its own really well in the market from a business standpoint, and only time will tell if their competition can do the same.
Anyways, that's my two cents. And full disclosure, roughly 80% of my observation optics loadout (including my tripod) is from Vortex, so take that for what its worth.