Scalability and State Bloat
Blockchains have an issue with state bloat. If there is no way to reduce the cumulative state of all past transactions, the blockchain state grows out of the capabilities of commodity hardware. This in turn will increase the capital cost of running a node and lead to more centralization.
Telos Zero transactions use a resource rent model where different resources (CPU, network, storage) are priced separately and can be exchanged or rented.
Storage on Telos (often described as RAM) has a cost, which is set via AMM type system (using Bancor algorithm). The total amount of data stored on-chain gives the size of the state. If a smart contract removes data from state, the RAM asset is returned to its original owner (the account that paid for the storage being recovered), the state size shrinks and that account can then sell the RAM back to the system if it wishes. Via this mechanism, responsible usage of storage is maintained.
Beyond state, the full blockchain history is also a necessary component of the overall blockchain functionality and can be scaled horizontally across a cluster of commodity hardware. The Hyperion history solution addresses this for both Telos and the tEVM using elastic search and is run by many Telos validator nodes around the world.