The main difference is that TON aims to develop an ecosystem around workchain and masterchain, while Polkadot's goal is to unite blockchains regardless of the hub. for example, the entire TON ecosystem revolves around the main workchain, while the Statemint parachain (analogous to workchain 0) doesnt have a major role in Polkadot ecosystem. Moreover, all developments are for the convenience of building projects on TON, while Polkadot / Cosmos has a goal to create blockchains on their core (Tendermint, Substrate)