What are the various city research projects like the Y Combinator initiative?

Firstly, there must be tons of companies that work on cities in general that ask similar questions:

https://www.sidewalklabs.com/

And secondly, every Urban Planning program is essentially a center to study how cities can be improved. Implicitly, the must ask what it means to improve a city i.e. what is the purpose of a city?

What is different about the Y Comabinator approach and do all these initiatives form a large network or are they silos?