The business idea is a separate concern. A solid business model can withstand all sorts of abuse and incompetence at all levels. Many eBay CEOs besides their best efforts to destroy the company have been unable to do so. Similarly for PayPal and a few other companies that have excellent product/market fit.
Each of those companies survives despite the best efforts of 1000s of engineers and managers to over-engineer and justify their salaries. So the logic of "1000s of people have worked on this so it must be valuable" is incorrect reasoning. The more pertinent question is how do these companies survive despite all the over-engineering that is happening? Once you ask that question you are almost surely led to the conclusion that the technology is not as relevant as people would like to think and inefficiencies at the technology level have very little effect on actual business outcomes when the product itself provides value people are willing to pay for.
Each of those companies survives despite the best efforts of 1000s of engineers and managers to over-engineer and justify their salaries. So the logic of "1000s of people have worked on this so it must be valuable" is incorrect reasoning. The more pertinent question is how do these companies survive despite all the over-engineering that is happening? Once you ask that question you are almost surely led to the conclusion that the technology is not as relevant as people would like to think and inefficiencies at the technology level have very little effect on actual business outcomes when the product itself provides value people are willing to pay for.