Something tells me "The Donald" is anything but an Introvert.
As far as the "I" thing goes I don't get it. No really. There are countless articles, even books written for sales, for self help, to.... about "Conversation". They all agree in that the absolute best way to get a conversation going is to ask the other person about.....? No, not the weather. Ask them about Themselves, or some aspect you picked up on. In other words, get them to use the word "I" because most people (most, not me) like to talk about themselves. It's a subject they are both knowledgeable and fond of.
Sure there are also plenty of etiquette books that admonish you for using "I". Then there are the grammer books with starting sentences and especially paragraphs off with "I". Most times it is impossible to avoid using. Now, EVERYTHING being about You, that is a far different thing. Other people also like everything being about them

I don't know if I'm truly an introvert or not. It is about as clear cut as the whole male-female thing going for me. I didn't do a lot of talking as a kid because I couldn't. I had a bad stutter. Especially under any sort of stress. This led to a lack of people skills. People skills that later need to hone in order to survive being a chameleon, trying to be a guy around various types of guys.
There is this veneer that is the outgoing, smiling, want to get along, "Salesperson" me that will skew results. Deep down inside being an introvert is safe. Being close to other people just opens you up to being deeply hurt by them.