Although Apple and Google’s voice assistants are shipped with far more devices, Amazon’s Alexa has become a formidable rival thanks to big investments and a swelling ecosystem. As much as Amazon’s Echo home speaker/voice assistant has turned into a surprise hit and yielded a blizzard of positive media attention, the Alexa voice assistant powering Echo hardware is still in key respects at a strategic disadvantage compared to rival offerings from Alphabet /Google , Apple , and Microsoft’s .