There's ~0 chance of that happening. Verizon can afford to completely write off $5 billion, so you would need some sort of poisonous cultural inversion for the deal to sink Verizon.
(Verizon is a much larger company, so if the Yahoo culture ended up dominating it would be an inversion)
(Verizon is a much larger company, so if the Yahoo culture ended up dominating it would be an inversion)