Apart from killing their third-party ecosystem, I think Twitter's biggest failure has been their inability to monetize their huge celebrity and brand base, and

Apart from killing their third-party ecosystem, I think Twitter's biggest failure has been their inability to monetize their huge celebrity and brand base, and I wonder if this partly has to do with their "verified account" system. How to charge celebrities/brands without pissing everyone off? Top-tier celebrities and brands can and would easily fork out high fees to use Twitter. But Twitter can't just charge some blanket fee to verified accounts because right now, "verified accounts" are not exclusive enough. They also include "key influencers", bloggers, industry people, other hangers-on (let's call them Group B) and they can't/won't support the high fees and would revolt. Twitter could try and create a new way to categorize celebs/brands, but that would confuse things and may make Group B users feel less elite: so they'd revolt as well.