Privacy considerations aside, I switched from Alexa to Google Home Assistant because Google is a search/ML company and best poised to understand a question and provide relevant context (like Google search result snippets).

Search is not Amazon's or Apple's main business so they will have a hard time competing. (last I checked, Siri just does a Google search and provides links when it doesn't understand a question)

However, both Amazon and Google seem to sell their devices at cost with the hope of finding a revenue model while Apple charges a premium for their Home Pod. That makes the Apple approach most sustainable at this point.