To expand a little on your first point - the market of people who truly love dogs, or love them enough to think of walking them to earn money outside of the Ube

To expand a little on your first point - the market of people who truly love dogs, or love them enough to think of walking them to earn money outside of the Uber for X economy, is probably tiny. Most people just have regular jobs and/or don't need the money that much and/or don't love dogs that much. You can scale the access to being a dog walker but you can't scale the "I give a shit about dogsness". Maybe the sharing economy model is just a poor one in certain cases?