Why is it that those with “big” and also “middle-size” names are saying they’re so damn open and easy to contact, and when you look for an Email or try to connect somewhere, they never respond, nor even accept an invite? Just bla bla bla as always.

I've found that higher level folks tend to reply to you if you at least take the trouble to catch them at an event or a speech. I think that is fair, you're asking for their time, at least take the trouble to locate an event they'll be at, show up, and ask for their email and introduce yourself.

They probably get hundreds of emails a day from people like yourself. If they took the time to reply to all of them, they would never get anything done. I would follow the suggestion of the first commentator.

I've had 3 billionaires respond to my emails inside of an hour when looking for a job.

Seriously, 3 billionaires. In less than -- one -- hour.

Keep your emails concise and make the ask, everyone has enough friends so don't just say hey I wanted to contact to say hi, give them a reason to reply.

There was already a thread here about this very topic; search and read through.

I think the biggest thing is to be cognizant of everyone's time and be clear, upfront, about what you need. I've been on both ends of this. Someone just wanting to meet for coffee is harder to make time for than someone that says they want to talk about a particular subject - or better yet has something to offer to the person they want to meet! Gotta give to get!

Try pitching them your plan in 1 sentence, 12 words. If that doens't grap their attention, don't bother putting your effort into it.

Try Linkedin InMails. With a good message and personal touch, this works 9 out of 10.