> How do you get to github?

  $ wget https://github.com/
  Resolving github.com (github.com)... 64:ff9b::8c52:7204, 140.82.114.4
  Connecting to github.com (github.com)|64:ff9b::8c52:7204|:443... connected.
  HTTP request sent, awaiting response... 200 OK

> How do you connect to news.ycombinator.com?

  $ wgetnull 'https://news.ycombinator.com/
  Resolving news.ycombinator.com (news.ycombinator.com)... 2606:7100:1:67::26, 209.216.230.207
  Connecting to news.ycombinator.com (news.ycombinator.com)|2606:7100:1:67::26|:443... connected.
  HTTP request sent, awaiting response... 200 OK

> Why is an IP address more valuable than an IPv6 address?

Because there's such an incredible amount of v6 addresses. You could pay a trillion dollars per second for a /64 and still only pay $1.70/year for each address.

> Why is IPv4 the incumbent 30 years after IPv6?

Because IPv4 was the only choice until IPv6, and replacing the Internet's L3 protocol is hard and takes a long time.