Investors will be interested because you have a plan to address an opportunity well, and not just because you have identified an opportunity that is interesting.
The success of an entrepreneurial venture depends entirely on the quality of execution. While ideas are important, just having a good idea is not good enough to start a company. Many companies fail to implement their ideas well.
That’s why while having a good idea is certainly a good starting point, and will be of interest to investors, they will eventually invest only if you have a good plan to implement the idea. And of course, that plan has to have an underlying business potential and business case.
On the other hand, you may have a strong plan around a concept that has already been implemented in the market by some others. If there is a business case, and if they believe you have the capability to implement a sensible plan well, investors will be interested.
In the Indian market, take the case of online travel agencies. After the success of Make My Trip, who was an established leader, investors did back brands like Clear Trip, Yatra.com and Travelguru.com, each of whom had a strong team with a plan to create space for themselves in a growing segment.