What amount of proof would be enough?
He could literally march out of the clouds and raise a forest from the deserts and you'd still have people who don't believe:
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It's an alien.
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It's an optical illusion.
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It's the devil himself!
There is already some proof, but it's not enough for people. There is no specific threshold of proof that is universally enough, thus providing additional proof is almost like showing favoritism to the few who the said proof is enough to cross their "faith" thresholds.
Ultimately, proof subverts the purposes of faith.
If you required guaranteed proof of your safety to drive your car, you'd never get in your car. At some point, you just trust:
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Your car will function safely.
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No one will make irresponsible decisions in your vicinity.
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… any number of other bad things won't happen.
Your threshold for travel safety has been sufficiently appeased. There are shut-ins who haven't had their driving risk aversion sated. That's not your problem, that's not the government's problem, and no is responsible for trying to convince those people that driving is safe.
Sufficient evidence exists (for most).