I used Chariot a bit a couple years ago. Sad to see it go. For people who haven't heard of it, it worked like this: I live in SF, and worked in Redwood City. Every day, there was some type of large van that would pick me up a couple blocks from where I lived and dropped me off a couple blocks from where I worked. So it was like a middle ground between public transportation and Uber / Lyft.
Isn't what you described an example of how buses work. I know very little about the state of public transport in SF but if it was better won't it solve what Chariot tried to do?
Chariot had a lot of smaller busses, like the size of those airport parking lot shuttles.
Personally, I'm really surprised at this. Chariot seemed to have a lot of corporate accounts (for things like shuttles to/from CalTrain to Company X), that I would have guessed they could charge a premium for.