In general, Decentralized apps / Dapp-s run on all blockchains which provide an api set for accessing of the specific blockchain.
A single Dapp can call multiple blockchains and do not need an ‘oracle’ to do this.
While the Ethereum blockchain is popular, the public mainnet is slow, overcrowded, often hacked and centralized - not suitable to be a sufficient solution.
Depending on the purpose, a private Ethereum or other blockchain will be better.
