Is the Bitmessage open source?
I think we can intergrate the bitmessage into our Nu wallet, and charge fee on every message. In this way, the spams issue will be resolved, and the fee rate is voted by Nushare holders if someone try to ruin/disturb this system in spite of some cost. For example, we can raise the fee to 1Nubit in urgency although 0.01Nubits sound good in common time.
Goodness is that the revenue is for Nu sysyem thus we can make profit to support Nubits buying liquidity. Some people may dislike not-free BM, but to keep private, we should pay something.