Stamp costs don't stop snail mail spam, either, unfortunately. I would be concerned if we added something like bitcoin fees to email delivery rather than curtail spam it would just further encourage grifters seeking ROI on their spam deliveries.
Some sort of payment scheme is really the best, most durable option. The problem of mailing-lists and personal correspondence could be solved by an exclusion mechanism where the recipient effectively whitelists senders, explicitly or implicitly (e.g. whitelist a replying-sender automatically if a recipient initiates a conversation).
So the end result will be more spam and fewer legit E-mails.
Hormozi could charge $1,000 to get into his read box.
We could refund people, add them to a whitelist - and return a 405? payment required by default and things change in interesting ways when the amount is variable.
I'm not sure you realize your proposal's only contribution is to worsen spam. You are unwittingly creating an incentive for email providers to lift anti-abuse filters and to maximize the volume of spam delivered to you.