That is not true. Two days ago lowRISC announced that OpenTitan used in Google Chromebooks will include CHERI:

https://lowrisc.org/news/opentitan-earl-grey-2-to-support-ch...

Last year, Google announced that their Coral NPU will include CHERI:

https://developers.googleblog.com/en/introducing-coral-npu-a...

There are more cores that companies are actively working on:

X730 from Codasip https://codasip.com/solutions/riscv-processor-safety-securit...

ICENI from SCI Semiconductor: https://www.scisemi.com/products/iceni-device-family/