This seems pretty clickbaity to me. There's very little content and no specific personal experiences discussed. What types of companies did you have better luck with? How many employees does a "startup/medium-size company" have?
This site also has articles entitled "The Must Know 7 Traps That Make Your Software Useless" and "Make Money with programming. Your Advanced Guide", so I'm not sure how high to set the bar.
The entire article can really be summed up as "Email the founders and get a recommendation."
Pretty accurate, only thing I would say is that I feel reaching out to a recruiter or a dev solely for a reccomendation is fine if you're polite and not overly blunt about it.
"Hey there, I saw your company was hiring and I wanted to reach out about X role. Feel free to reach back out if you feel there might be a good fit or if you have time to talk more about roles at Y."
I guess he meant it in a broad term and it's up to you to get creative. Now that I think about it, you can start by complimenting the resume for the employee you are interested in, and ask how he/she got there. Generally, if they are open to helping they’ll drive the discussion forward. Needless to say, if your first message/email is "please recommend me" it won't work. Personally, I always get back to first principles: Provide value first before asking something back.