Russian Startups on the internal market

I found that some web startups are trying to sell theirs self immediately after the start. That means, "the entrepreneur" created the nice site, had found the idea and then he likes to sell all the business to someone else. I can't understand that. I know that performing of the idea is the most difficult part, but it's wrong to sell business without any implementation.

I am sure that idea cost much less then realization.

Example:
Initial investments: 2000$ (very much)
Investments to be added: 20000$
ROI: 300%

I can't imagine how it possible to calculate the ROI (a very big ROI) at the start of business without the real results.


I think this is not a good practice.