there were a lot projects with sharding (for example the 1st one was Zilliqa, than Quarkchain etc). But who need this TPS without usecase? There are hundreds blockchains with enough TPS but without usecase and adoption.
Decentralized finance, DeFi, needs more than only scalability (lots of TPS). It also needs composability. Other projects that have been using sharding to increase scalability have done so at the cost of composability. The Radix approach increases the first without breaking the latter. With a decentralized ledger technology that enables both, Radix provides the infrastructure for usecases and adoption that before was lacking.