Reasons rust has dominated so far:
- Rust has a bunch of existing libraries that can be leveraged as long as you are doing only small bits of work in your contract.
- There are more Rust devs.
- Until last week Motoko didn’t have call_raw and rust did so certain applications were off the table.
- Motoko still doesn’t have inspect_message so it may be more susceptible to DDoS attacks.
My thoughts are that once we build the core libraries for motoko it will be the preferred language and prone to wider adoption than rust.