> I can't pull out my visa card and go buy a (atx, microatx, mini-itx) format motherboard for an ARM CPU, the CPU itself, RAM, etc, and build a system to run debian, centos, RHEL, ubuntu whatever on.
The difference between ARM and x86 is that there's no standardized ARM interface between the motherboard and the CPU—no ARM equivalent to ACPI. Every integration of an ARM CPU into a board is bespoke. So you have to buy "a board with an ARM CPU on it", not just an ARM CPU and board separately.
But, if you relax that restriction, it's not like it's hard to acquire "a board with an ARM CPU on it." 80% of single-board computers (e.g. the Raspberry Pi) are "a board with an ARM CPU on it." You can wipe pretty much any Android device (not just phones, but also HDMI "streaming boxes", which are a convenient form-factor for basing a workstation on) and install Linux on them. There are also some higher-end development/SDK boards for ARM embedded systems, like the Nvidia Jetson. What more do you need?
The difference between ARM and x86 is that there's no standardized ARM interface between the motherboard and the CPU—no ARM equivalent to ACPI. Every integration of an ARM CPU into a board is bespoke. So you have to buy "a board with an ARM CPU on it", not just an ARM CPU and board separately.
But, if you relax that restriction, it's not like it's hard to acquire "a board with an ARM CPU on it." 80% of single-board computers (e.g. the Raspberry Pi) are "a board with an ARM CPU on it." You can wipe pretty much any Android device (not just phones, but also HDMI "streaming boxes", which are a convenient form-factor for basing a workstation on) and install Linux on them. There are also some higher-end development/SDK boards for ARM embedded systems, like the Nvidia Jetson. What more do you need?