A vast majority of these boards use chips made for mobile phones to keep the costs down - so we have to make do with what these chips have. Which is why they su

A vast majority of these boards use chips made for mobile phones to keep the costs down - so we have to make do with what these chips have. Which is why they support 2 or 3 camera buses, WiFi, LVDS, HDMI, Bluetooth, SD, but usually no SATA, no PCIe lanes, no Ethernet (it's often a USB device like on the Pi). The Pi is pretty much the only one with the sales numbers to justify the cost of a customization, but even that would be a small miracle.