Next Billion-Dollar Startups 2019

Couple of observations i had from reading about all the companies.

1)I wonder if we will begin to see more and more "billion dollar" companies have products which are more abstract in nature than previous generations, there seems to be a shift from previous "billion dollar" companies which had relatively simple to understand products (social network, search, eCommerce, taxi, housing)

2)No real relation between projected income next year and investment taken

3)Most founders seem to be veterans of the industry rather than "straight out of college" types, i wonder if this goes with point # 1, where a specialization in a domain is more and more required for founders of the next "billion dollar" company.