This comes at the cost of what is good for the company. Using Facebook as an example, you would sell Facebook when Viacom wanted to buy it for 75MM. Great huge return for investors for such a young company. Can turn around and show your fund had a huge exit. Especially great for a seed fund but terrible for the founder and the employees. Luckily, Zuckerberg had control and could thwart investors desire for a quick sale. [1]
I am totally not against VCs making a return but what I am against is VCs forcing premature exits. We may never know what Twitter could have been if the ecosystem stayed in-tact and they figured out how to monetize the whole thing and kept the user growth trajectory in place.
[1] http://www.businessinsider.com/all-the-companies-that-ever-t...