Ask HN: Why can't we have a single Arm standard for os' and apps?

Fragmentation in Arm ecosystem is just overwhelming. First, not 2 hardware platform can share a single os install script. To each its own. Pi here, Rockchip there, Alwinner, whatever. Even within a single company, you need as many flavour as there are boards. Then, on the software side, not all arm app versions works everywhere. I'm well aware of the multiple obstacles in the way. I'm just asking: why not agree on fewer compatibility standards? That would help a lot in making arm more usable.