Personally, I'd like to see paid relays make the experience better in a way that naturally monetizes.
Example: I own a hypothetical relay that filters out bots. You insta-reply within milliseconds with the same regurgitated "air drop" bullshit, my users don't see your replies. Because it cost you nothing.
You want your airdrop message to fall on deaf ears anyway? There'll be an incremental cost of business to do so.
By applying a cost to the "advertising" that's already going on, we both diminish its frequency and provide a revenue stream.
Users get a better experience. Relay gets paid.
*Great oversimplification, I'm sure.*