In theory: No, but it might make sense to make the difference between Ubuntu and all other Linux distributions clear. Maybe Ubuntu should not be called "Linux"

In theory: No, but it might make sense to make the difference between Ubuntu and all other Linux distributions clear. Maybe Ubuntu should not be called "Linux" anymore, just like android which also uses the kernel but has it's own userland. In practice: Yes, Cannonicals questionable open source policy could throw free software desktops a few years back. Just look at Mir for an example. EDIT: or hdevalences comment below!