I must be missing something.

I got the bug from here and others to get credit cards with bonus miles/points. I have read many threads that show folks churning to get 500K miles or even 1million over and over again.

How is this possible with Chase being the biggest/varied awards offerer and you can only apply for their cards once and get bonused once only.

Citi you have to re-apply after 18 months on personal card and 6 months on biz...

The timelines just don't make sense that some folks are able to do this on a yearly or so basis.

Appreciate a bit of insight here.