Firstly, I must say I am completely flattered that you noticed my little comment and blew it up into this Ask HN.
Secondly, you are absolutely right that it should be addressed.
Some people are saying here that these investors gave Carson the $5MM because they have so much money that 'wasting' $5MM is no big deal. It doesn't quite work like that.
For starters, being an investor with a ton of money, you don't need to buy access to Carson. I can pretty much guarantee that people like Ron Conway, Peter Thiel, PG, Marc Andreesen, even if they didn't invest in Treehouse if they wanted something from Ryan Carson he would jump (as most rational people in the tech space would rightly do) at the chance to help them out.
If Carson took their money, with them assuming that there will be an exit - when he knew full well that he wasn't interested in one....well.....that's dishonest.
If he was very straight forward with them, which from everything I have read about him I assume this is the likely route he took, then he probably did discuss with them exit routes he will take (i.e. an acquisition).
The issue is, as an executive (especially a chief executive) you have a fiduciary responsibility to maximize shareholder value.
If you know, that your ONLY exit option is to be sold to a larger company, then publicly getting rid of your other "legitimate, best alternatives" essentially squanders this fiduciary responsibility.
In other words, if I want to buy your company. You want to sell it to me for $50MM, so all of your investors can make a good return, why would I pay that if I know that I can offer $30MM and you would be hard pressed to take it.
The only way for you to realistically bid up the price that they pay is if someone else wants to buy (or you want to take it public). You can't assume that someone will "always be there". That seems irresponsible to me.
The one option that every fast growing tech company has, is to go public. So it seems like a mistake to piss away that option for no upside.
Edit: Cisco's acquisition of Meraki is proof positive of my theory of having a legitimate alternative of going public - http://www.meraki.com/company/cisco-acquisition-faq
From the CEO of Meraki:
So, when Cisco approached with an acquisition offer a few weeks ago, our initial reaction was to politely say "thanks, but we're planning to do our own thing and take Meraki public". It turned out that was exactly why they were interested in talking to us...