I'm going to add:

4) The penny-pinching RPi does on hardware: be it RTC, usb power kerfuffle or ARM crypto extensions (finally added in Pi 5)

5) accessory lock-down: see the situation with Pi cameras, or better yet DSI displays (CM4 datasheet: Although Linux kernel drivers are available, the DSI interface is not currently documented. Only DSI displays supported by the official Raspberry Pi firmware are supported.)

6) half-assed documentation (if you know, you know)

7) the ever-present marketing to compensate for the previous points, and the fact that it works

This is exacerbated by its popularity so people tend to treat raspberry pi as a hammer for all of their nails, while in many cases a 2$ mcu would suffice or a more network-capable SoC would be a much better fit (raspberry Pi NAS, pihole etc).