Here's a counterpoint why it might be a viable business: it unlocks a new market. Scooters enable a new class of trips: trips between 0.5 and 2 miles. There's currently not a lot of trips happening in that distance... below that you can walk, above that you take transit, but that coffee shop 1 mile and change away is just enough of a pain in the ass that it's not worth going there. Unless there was something that made it easy to go that distance.
Scooters are a new modality of transport that opens up an entirely new class of trips. Combined with the fact that the population is broadly trending towards dense urban environments, you have a whole new market you've unlocked.
Scooters aren't about replacing Lyft rides -- no one uses a scooter for a full hour -- scooters are about servicing trips that are too short for an lyft.