What are the salient factors to decide the technologies to build a product?

Hi . This is Ritwik form India and I am a web developer.
I see a lot of entreprenuers launching new products. I am curious to know what are the salient factors to decide the technologies (e.g. which server, which programming languages , frameworks etc) to build the product. I would love to know both from entreprenuers who are developers themeselves or those who have engaged other developers for the development part. Thanks.