1) The implementation of the wake word recognition is implemented in hardware that cannot be updated remotely.
2) The device is unable to transmit information without lighting up a TX light. Implemented in unmodifiable hardware.
3) Voice recordings are processed and then deleted within one month.
4) The device is run by a company that doesn't make money through marketing or data analysis.
1&2 get the company pilloried by HN the moment a vulnerability comes out.
3 is a requirement that doesn't actually solve any problems and ruins a legitimate need of ML - comparing performance against a known baseline.
4 is overbroad - most software companies make their money through data analysis of one form or another.
You're setting up an impossible set of demands that no manufacturer is going to meet and no consumer really cares about (other than perhaps yourself and a few tinfoil hat wearing crypto-anarchists).
I trust Amazon as much as I do Apple to protect customer privacy.
Pain in the ass but you could open source it for the rest of the world.