That is factually inaccurate. If the total float is large enough to make a market, then the amount of stock closely held is irrelevant. If I can execute an online trade in the amounts I need at the price I want, then the float is adequate. Today, a retail investor can purchase small quantities of any listed stock for an online commission of $4.95 flat irrespective of the share price. In 23 years of self directed investing, all of my trades have been for a minimum of 5 shares and a maximum of 200 shares on both the buy side and the sell side. I can tell you that the total commission costs ranged from a high of $29.95 per trade (ca. 1994) to a low of $4.95 per trade ( ca. 2017). These costs are like fly specks in the pepper.I've had a copies of the 10K report for several large tech companies (Google/Alphabet, Yahoo, Facebook, etc.) in the S.F. area and that vast majority of their stock (about 60% to 80%) is owned by a relatively small number of principals (like about 25 to 40) rather than the public.
Furthermore, their stock is sold in a minimum quantity (like 1000 shares) and that's beyond what your Average Joe small investor can afford. There are also broker's fees to buy or sell.
So buying stock in a large corporation is not an option for most people including the rank and file workers. Unless you're a major shareholder, management is not going to listen to anything you've got to say. That's where unions got rooted in big industry.
When I started my IRA in 1976, it was true that commissions were quite a bit more. I made maybe one trade per year and it was always a buy. At the beginning it was Intel, then Oracle, then Texas Instruments. My memories are imprecise but those commissions were in the $80-$180 range. Don't get me wrong, I am no Warren Buffett. But like Buffett and other great investors I was never fearful about investing because I had a day job, and a long time horizon. My day job is long gone and my time horizon has shrunk to near zero so the risks I am willing to take have changed. Getting rich quickly is incredibly hard, getting rich slowly is eminently doable.