I'd love for either the Warpcast team or a dedicated client for direct casts offer a pay to message feature - you pay into escrow, and if the other party responds, the funds are sent to the other party

This incentivizes responses to important DCc, and esp for some people it literally puts a value on their time

You could probably enhance it further by letting the sending party decide whether the response was satisfactory before releasing the escrow funds

This could all be done with Warps or USDC

We've considered this, but I suspect the people the market would value the attention of the most aren't motivated enough by per message fees.

Still may be useful as a primitive for marketing messages, though.

Thats a fair assumption

From a marketing standpoint it might be really useful

If I'm launching a new project using the Farcaster social graph as the GTM and I have a bunch of priority users to engage with and onboard with, I would pay a reasonable sum to ensure that my message gets through to them

Perhaps its not a per message fee but a monthly subscription to DC Priority mode - if you use it your messages are pinned at the top of a users DCs until they open/respond