It would have been hard to achieve anything else. Those were, overall, excellent years for stocks. The large drop in 2008 meant you were buying at a discount early on. Also, small sample size.
I doubt it, and so does science. It doesn't matter whether a company pays out its profits to shareholders, or invests them to grow the value of the business. Only the tax treatment might be different. This is all really well researched - you could look it up!
Not meaning to rain on your parade, though. Personally, I think investing in individual stocks rather then index funds is fine. That is, if you have a large enough portfolio to keep transaction costs small and do a good job to cover all segments of the market, domestic as well as international. Global exposure to all kinds of different businesses requires dozens of stocks, after all. And focusing too much on dividend payers will likely lead to a portfolio heavy with large value stocks.
Lastly, what many folks on this board correctly criticize is not so much holding individual stocks, but the believe that stock picking and market timing will result in outperformance. Going with low cost index funds is just much simpler, and just as likely to succeed. That being said, I, as many others, do buy the occasional stock in my "fun money account". It's simply much more interesting, and it makes me feel good if I'm right. But for serious investing, I trust Mr. Market more than my own investment skills.