You don't need "massive support infra in 100's of languages". Start with English and see if it works. Then expand slowly, making sure the service remains profitable each step.

An add-on of the kind I'm suggesting is exactly the way to serve both a mass market and a niche at the same time. Everyone uses Gmail, but the few who want support for personal use pay. That's much less effort than building another product with paid support.

It's also no different from freemium mobile apps where 2-5% of users pay.

Google decision-makers are smart, but not infallible.