In the blockchain, each subsequent transaction stores information about the previous ones. Transactions are related to each other as links of one chain — a block. Blocks cannot be modified or removed from the system without destroying the entire chain first.
The fundamental difference of Telegram Open Network is that instead of new blocks, new blockchains (new ledgers instead of new records) will be created in the chain. This will allow dividing the entire array of operations between smaller chains (which are also interconnected). Multi-level blockchain can provide a high bandwidth for transaction output.
The infinite sharding (automatic split and merge of the TON network blockchains) is the solution to the blockchain scalability issue. As so, the TON blockchain will be able to meet the needs of any number of users.
Here's some food for thought: how many resources will be needed to maintain such an extensive platform.