Yep, this is totally on them. It's led me to stop using their video products, and we're not renewing Prime after this period expires.
Amazon would prefer I buy their Fire TV stick thing, which they would then use as a hook to sell me more Amazon stuff. Given Amazon's attitude towards Apple and Google's streaming devices, chances seem decent to me that if Roku ever increased its market share then Amazon might cut them off.
I'd rather just use another streaming video store.