We don't know that. We just know that we're not familiar with them. If anything, globular wheels could make some kind of automated steering easier.
And of course, it's obviously not like Apple only tried that design: they tried globular wheels, fat wheels, thinner wheels, wooden wheels, and what have you to see what works better -- like they did when they designed the iPhone, etc.
https://www.cultofmac.com/181782/every-iphone-prototype-appl...
https://www.theverge.com/2017/1/6/14188624/apple-prototype-i...
Yes, and 'standard wheels' would have saved them time, money and other resources and would have increased the chances of bringing a self driving car to market.
Time from what? It's not some team considering other kinds of wheels was holding back their self-driving researchers...
You seem to have an overly linear and heavy-first concept of how such a development should go.
Solving too much is a fantastic way to crash a project.