I have had two windows phones, and the first was a WP7 based device that was upgraded to 7.5 (maybe even 7.8, although I had since sold it if it did).
The second was the 8X, and if I am not mistaken, it recently got a software update as well, which is also rolling out to other WP8 devices.
Even the devices at the end of wp7 cycle got an upgrade to 7.8. Maybe there are other devices that got left out in the cold, but it appears, admittedly at a very brief glance, that Windows devices are getting at the very least, a comparable level of software support that most androids will receive.