Evidently, a study from Microsoft inferred that more people use Siri than Amazon Alexa and that it's on par with Google Assistant for usage in the US. Titled "2019 Voice report: Consumer adoption of voice technology and digital assistants", the study is based on two online surveys that run from March to June 2018 in the US, UK, Australia, and Canada, as well as February 2019 in the US, where it has collected responses from 5,000 people.
The report, suggested that both Siri and Google Assistant accounts 36% of share in terms of US usage, Amazon's Alexa, meanwhile, despite being widely used in the world's most popular speakers, Echo, it only earned a third place with 25% of market share, and Microsoft Cortana eats pretty much the rest of portion.
The 44 page-long paper also listed other interesting tidbits, such as when asked what concerns users have about digital assistants, 52% participant worries their personal information or data is not secure, 42% questioning whether they are being actively listened to. Also, the research predicted that by the year 2020, 75% of households will have at least one smart speaker.
I personally think that Apple should take the chance to introduce a low-cost smart speaker to compete with Amazon Echo Dot and Google Home Mini as so many folks are considering purchasing such product, because they only cost $50, whereas HomePod is available for $299.