Totally agree with your point. Was off right at the start with this :

some mechanisms to apply in the process of UX/UI design in order to make the product more or less viral that means promoted by users and therefore saving time, money and efforts on marketing.

Virality in itself cannot be designed. If it could be, everything would be viral, thus nothing would be.

You can put time and effort in designing a complete product that will fulfill a real need, and then you will have some chances that it will grow in popularity, but even some AMAZING products have failed at gaining users.

The advice given in this article are basic generic facts that any real designer already does. It’s just a job description..