Does blogging with popular cms like wordpress makes my website an authority website in SEO?
does blogging on popular cms platform like wordpress helps in SEO as compared to using a proprietary CMS?
No. It's about quality of your content, uniqueness, trust!, reliability. (You don't have to be the number one search result at any given time, btw.). It's not necessary that your content, your page or site is over-optimized.
No. There is a lot of fetish out there when it comes to optimization features in different tools. Focus on content, on social signals, avoid black hat techniques and looking spammy. You get no bonus if you use wordpress. There's just a benefit for you as you get lots of documentation and optimization tipps along with some nice plugins.
If you are using wordpress or other CMS does not mean you have all the way up. You can use a proprietary CMS and achieve almost everything that wordpress does... but, is very hard create a CMS by yourself better than Wordpress.
So, what are the SEO Benefits Of WordPress?
You can find more info about this on the Wordpress Core