Thanks for the comprehensive post. Here are my 2 cents:
I think the entry of MVNOs can change the industry landscape as it shall give a new dimension of competitiveness beyond price. Telco experts in India believe so as the Indian regulator is about open license for MVNOs soon. You may read more about the case in India here.
I like how you defined the 3 horizons of innovation which -in few lines- perfectly describe the top challenge every company faces specially as it grows big like a fat cat! I believe Yahoo is another solid case demonstrating how failing to innovate in one or more of the 3 horizons can lead you to catastrophe after catastrophe!