They're only starting in NY and Cali, which I estimated to be about 7 million dogs that needed walking. Additionally, Uber and Lyft combine to do $8 billion in revenue per year, operating at much larger scale with much larger demand and averagr sale price.

So I think $500M a year is optimistic. I would expect this type of startup to do more like $50M a year in revenue with a modest loss, and the users are then sold peripheral pet services.