This is dPos. Those witnesses would also need to be voted in with massive amounts of stake in order to 'take control'. Simply running a large number of witness nodes would not achieve that effect.
Why build your own chain when you can get one that is already established, comes with an existing large community and support, desired social features, and your own token with which you can still perform an ICO if you wish (SMTs)?
Why wouldn't I? (I, like a strong website)
I could make my own rules, my own settings. Code is already open-source, thus I know how to do it. That coin would serve as an extension of my brand. And that coin would not have the past that is maybe negative.
In other words, very small infrastructure could de novo mine Steem-like token with some upgrades, and the whole mess with fake whales, bid bots, blah, blah, would be avoided. The graph on coinmarketcap would be pointing upwards, not towards zero.
They are not going to invest in this coin, it would be a business suicide.
The only way to maybe bring some strong player would be to bribe them with a massive amount of coin. Coin with low value. Coin that you (Inc.) had, and now you have much less.
Again, crown example, @rt-international came - what have you done to get their public support and to get some exposure in media?
Or, even better question. How many websites are using Steem (that stuff, much larger than Steemit) and what is the total traffic they have? After 3 years. Which of those websites, platforms is the most well known?
Also, who is the most popular Instagram star who joined Steem(it)?
And who is the most popular Youtuber?
Any celebrities?
There are only three options: