Please advice: Is Backlinks Amount No Matters now?

Hello Members,

I was investigating websites ranking for keyword like "federal firearms license" in google.com . And following site i found in first page of google (position 7th) is hxxp://www.americanthinker.com/blog/2013/04/gun_shop_that_sold_newtown_weapons_loses_federal_f irearms_license_comments.html

This page consist of 1 backlink (check this report)
- https://ahrefs.com/site-explorer/bac..._comments.html

The source of 1 backlink is - firearmslicensetips.com/federal-firearms-license-in-south-carolina/ .

Now, i checked the page (firearmslicensetips.com/federal-firearms-license-in-south-carolina/) in visual mode and cant find any back link. But when i see the source code of this page then able to see that 1 back link - check this screenshot http://screencast.com/t/5XJ3ItW9

My questions:

a. How come a page get ranked in first page (competitive keyword) of Google just having one backlink. Is backlinks now not matters ?

b. How the backlink showing in source code but not from visual mode. Are they using doorway page ?

Please forgive me, if this question sounds too simple. I tried to search the answer in other threads but i cant able to find. Please advice.