Wouldn’t the solution be to just start charging for excessive DNS traffic?

Potentially yes, but that's a business decision which the on-call developer cannot deal make on behalf of the business.

There's a lot of stuff the dev team can do that are not strictly business decisions though. Rate limits, QoS, etc.

	▲	rapind 3 days ago \| parent [-]
		Those can be business decisions too though. It depends on whether or not the real / lucrative customers will notice, or maybe the noisy customers who will be all over twitter because a dev figured they'd make a big change like this on their own. Throttling and tiering can definitely affect more people than you might suspect (like spiky services) and considering data and use are important.