In their defense, ARM11 is a 10 year old chip. I don't think they want to support such an old legacy. Does Windows 7 support Pentium 2?
Still, I'm hoping Raspberry Pi moves to Cortex A7 as soon as it's available, which is based on the ARMv7 architecture, and Canonical might support it then.
Debian has two ARM ports: one that supports ARMv4 and newer, and a second that supports ARMv7. It looks like Fedora is pursing the same approach. If they have the expertise and resources to do this, surely Canonical could do it too if they thought supporting older ARM devices would benefit them.
The PII is 15 years old at this point, 10 years ago was Northwood p4 and the Athlon XP for AMD
Those chips started at 1.6 and 1.33GHz respectively, and Windows 7 requirements start at 1GHz. RAM might be a dicier issue (W7 requires 1GB) and I don't know the state of the chipset drivers, but technically W7 probably supports x86 chips from 10 years ago.
i586 has stayed backwards-compatible (although performance isn't the same if you don't know what you're targeting), ARM hasn't. The raspberry pi's ARMv6 is very different from a Cortex's ARMv7. The kernel also needs patches to know how to initialise an ARM device, and those patches need to be forward-ported.
Still, I'm hoping Raspberry Pi moves to Cortex A7 as soon as it's available, which is based on the ARMv7 architecture, and Canonical might support it then.