Your examples all are for simpler chips, more microcontrollers rather than application processors (with the chip on the Teensy 4.x being the closest to the latter category, it's a bit of a hybrid). Those kind of boards also typically do not expose much that's specific to the capabilities of the chip, but rather mostly jut raw access to the IO pins + some helper circuitry. That's not to say you can't use those to develop things with the chips, but it's a somewhat different market.

Whereas from a classic development board it's typically expected that it provides access to as many capabilities of the chip as possible, and more complex chips have a staggering amount of those. E.g. taking the chip on the teensy, since it's the one that's the most high-end one from your examples: It has Ethernet support - add an Ethernet port. It has CAN support - add external CAN circuitry. It has USB - add USB ports. It supports low-level debugging through JTAG and SWD - add that, either a basic debugger or at least a space to connect an external one. It has a display interface - add a dedicated header for that, or maybe even just add a display. I think it supports eMMC flash - add space for that. That makes these boards a lot bigger and expensive, but it means a developer can start with whatever combination of things they want to try, and if the alternative is them spending a day on figuring out and hooking up all the external bits they need on a simpler board the higher price doesn't matter anymore. (Especially coming from the days were there wasn't as big an ecosystem of breakout boards for lots of things available).

The end result then looks more like something like this: https://www.embeddedartists.com/products/imx-rt1062-develope..., and appropriately costs a bunch more than the teensy Teensy.