There really isn't that much complexity from different hardware configurations. Almost all computers can be covered by drivers for AHCI,EHCI,xHCI,HDAudio, and vendor-specific drivers for graphics and network. There's no longer any need to worry about interrupt sharing or other conflicts between subsystems, so introducing new alternatives doesn't have a multiplicative effect.
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There really isn't that much complexity from different hardware configurations. Almost all computers can be covered by drivers for AHCI,EHCI,xHCI,HDAudio, and vendor-specific drivers for graphics and network. There's no longer any need to worry about interrupt sharing or other conflicts between subsystems, so introducing new alternatives doesn't have a multiplicative effect.