The ICO craze has enabled a lot of these developers to just march out on their own and start coding, make a website, answer telegram questions etc etc, all the while thinking that they are doing something truly unique. They forget that at the end it is a business and they need a product. A product needs marketing, advertisement and all that shit. Yet, the problem with most of these so-called undervalued, good devs is that they all think they are on to something unique. It is impossible for everyone to be a Satoshi or a Bill Gates and make a business from scratch simply on the basis of the novelty and brilliance of their ideas. The echo chambers of their telegram/ Reddit groups makes it all the more easier to fall for this narrative.
They all could do much better only if they used some business sense and actually invested in marketing their product, meeting potential clients and just run an actual business.
There are so many factors that will contribute to the success of the project, but it starts with the developer, the developer is the one who gives the idea materialize, but without marketing and investors it's nothing even a simple idea turn into great things as long as there are supporters and proper marketing, these are the three ingredients of a successful project.