Are you serious? You mean that in general, or in this particular case? Frankly, I am shocked by your assertion. Quoting Andy Grove:
"Intel never had an exit strategy. These days, people cobble something together. No capital. No technology. They measure eyeballs and sell advertising. Then they get rid of it. You can't build an empire out of this kind of concoction. You don't even try."
My thoughts exactly, only expressed more eloquently. What do you want? Make a couple of million and spend the next 30 years bored by the pool drinking cocktails? Or do you want to build an empire? Sure, building an empire is hard work, but at the time of my death, I want to know I chose the path of adventure, not the easy way out.
I am by no means advocating taking enormous risks and chasing quasi-impossible dreams. But if one's startup is taking off, why not stick around and try to scale it up? Building a company of a few 100s of people from scratch sure must be a whole lot of fun. You are creating employment, you are creating wealth. If you sell your business as soon as it starts working, then you do the hard work, and someone else gets all the credit and the fun.