Reducing Spam via Wallet Exhaustion

Initial High-Level Proposal:
Implement a heat threshold to wallets. Newer wallets with a short history and few transactions on the network are born with a low heat threshold. How aggressively accounts issue transactions on the network will increase the heat of the wallet, similar to a car overheating and blowing its engine.

As a wallet matures, it will gain a higher threshold to heat and their value could more-or-less cool quicker than immature wallets.

The network's ecosystem would more-or-less stay the same, however, spamming the network would be easily identifiable and mitigated as wallets that are aggressively using the network would overheat quickly and lag themselves to slower transaction processing times. Backlogging them based on how hot their wallet is.