Not only did it result in the poor making less but the cost of living went up.
[0]: https://www.vox.com/the-highlight/2019/7/13/20690266/seattle...
Every-time they've been put in place in this systematic way it's led to greater economic mobility, greater employment rates and a lowering of the burden on social welfare systems; whilst having little demonstrable impact on long-term economic growth, and in fact, there's recent evidence to suggest they have net positive impacts on growth[0][1][2][3]
What Seattle represents is a small isolated experiment within larger state, regional and federal contexts that effected its outcome. That's not to dismiss it's value, far from it, but to take as it some kind of definitive evidence is to weigh a grain of sand against a beach of contradictory evidence.
[0]: https://equitablegrowth.org/working-papers/distributional-mi... [1]: http://www.lse.ac.uk/business-and-consultancy/consulting/ass... [2]: https://assets.publishing.service.gov.uk/government/uploads/... [3]: https://www.nber.org/papers/w25434
Also
> Surveying employers, Romich and other researchers found the most common response to the wage increase was to raise prices