Finally, I could outrank my top competitors with adding more links!

Today, I'm really really happy too much because it's the 60th day that I'm tracking my rank. My site stood in the 2nd position of a very hight competitive keyword. I spend a lot of money, time, and effort to outrank the no.1 position site. I built up many high quality content over years. Moreover, I even build PBN exclusively for only this site. I outsource and spend much money of link building. It ended up on the 2nd position even how hard I add more quality links and diversification, it would not jump up to position 1 for a long time.

3 months ago, I decided to move this site over to a very high end fast cloud vps hosting which literally costs more than a regular dedicated server. I bought MaxCDN and more zones for this site alone. I started optimizing my site speed by removing unused bit of css, JavaScript, html, and unnecessary codes even one line of unused code, I won't overlook. I optimised all the images and ament html theme structure to give more easy path in order to make it fast crawling by SEs.
My site incredibly improve a lot in term of speed and structure. It decrease the 3 Seconds load time to only 0.4 Second for a very intensive WordPress site.

After optimising, only 1 month it is on position 1, and the 1st one become 2nd. My site sits on the first position for 2 month now. I didn't do anything with link building except on site performance and content.

Finally, today is the 2nd month that I stand still on no.1 position. I'm nearly crazy and super happy because it's increasing my ROI about 270% with just one rank.

I assume that speed+site structure is another important factors in ranking with Google for me if not yours.

Therefore, I'd say that choose your theme for your money sites carefully. Don't be fond of the many option panels that could cause many queries and lead to slow responding.