Is Starkware a threat to Zcash?

yes, the ZF has a wider goal list than the ECC, which is what led to some questions about how the ZF could/would spend money that offended some people, but the ZF seemed to reply that their focus is on zcash.

And the ECC is who funded starkware, not the ZF.

And the ECC’s mission is solely on zcash and spreading zcash adoption.

Edit: These are the posts I was referring to about ECC vs ZF’s missions and concerns that came up, which showed that the ECC focuses on zcash only (or partnerships that help zcash as well)

https://forum.zcashcommunity.com/t/thoughts-on-conflicts-of-interest-within-the-zcash-foundation/41679/3