Having android free, has allowed the manufactures to make a whole range of devices with no licensing costs, where as for Windows Phone, they have paid for the one device.
Microsoft gets this finally and 8.1 has less limitations in that regard, but this just means there is a lesser risk in producing phones for Windows Phone.
If 99% of your phones you make most money off are Android, you’ll continue pushing Android front and center.
The other major issue and still hasn’t been addressed is that companies are able to seriously customize the OS in Android, but not Windows Phone.
This allows people to choose between Stock (Nexus), HTC, Sony, Samsung, based not only on the phone, but the custom experience. Without that customization each device for windows is based only upon the device quality, not just user experience, since it’s all the same.
Imagine HTC was able to add it’s flow UI back to Windows Phone. It would be huge, they would have tons of folk buying HTC devices over Nokia devices. Before Android, before iOS, you wanted an HTC Windows Phone because of their customization compared to the competitors.
I hope that MS will allow this and not just push the one experience for all approach.