Respectfully, zone count does add cost. In major ways.
An edge-lit can be made with as little as a single strip of LED at the bottom of the diffuser.
A cheap backlit (<100 zones) uses several LED strips at the back of the diffuser.
Typical dimmed backlits (200-500 zones) use a full-screen PCB. Full-screen PCB are expensive.
The more zones, the more expensive. The wiring for 1K+ zones will push it from $100 to past $200 per square meter.
And of course more LED are more expensive than fewer more powerful ones. Pick-and-placing more LED is more expensive.
Reduced-bleed FALD use an additional 3D structure
and a non-standard diffuser. That adds further costs.
Similarly, dual-LCD mean two panels instead of one, two controllers, and brighter backlight, a step further in cost.
For years, the LCD industry was all about making things as cheap as possible, then throwing the consumer a new bone each generation to placate them. Some useful like 3D or 4K, some less so like curved screens, but all cheap to make. Now it's finding itself in need to throw some money at the product to make it competitive.
This will certainly work to maintain more niches for LCD screens than just low-end granny TVs. However, it's also happening as OLED is pushing down its manufacturing costs, and the base technology itself is simple and scalable. So LCD's future at the middle of the market is very questionable, seeing how the base tech is non-competitive quality wise, and the remaining quality improvements are not well cost-scalable.