I would say part of it is that ARM never really had wide spread socketed chips. It's pretty much just always a soldered highly integrated unit.

Go go back far enough you had a point in time for example you could swap an Intel or AMD cpu onto the same motherboard. Also using expansion cards for additional hardware capability was the norm. So software kinda evolved to handle disparate configurations of hardware.

ARM evolved differently. It end up being to be used more in embeded and then SoC systems. Hardware around the CPU and later on Die ended up with often a unique configure for the system/device. So the need to handle disparate hardware configurations was less important. Also the way ARM licenses their IP definitely pushed things to be more like this.

RISC-V atm is often being used in place of ARM so a lot entities are kinda are treating similar to ARM when developing a system/device. However, RISC-V since it's an open license on the ISA does not have to be used in similar way. Like imagine if there was some standardized socket for RISC-V chips and that took off, we would probably see things like UEFI and drivers/kernel drivers meant to work with more than just one single configuration of hardware ect...