The exchange platform backs up the project so if you have trust in that exchange, then the possibility that the investment will produce better profit is high. If ever the project turns out as a scam or the owners have ran away, it will sure stain on the reputation of the exchange. So, aside from choosing a good project, you first need to find a trustworthy exchange.
both aspects must be considered and analyzed carefully. because conceptually a good project will choose a good exchange for their community. that's if the developer is indeed planning big in the future with their platform. but that does not provide a strong guarantee, other scammer factors can make mistakes as you say. IEO is now more popular and more widely used. but this system has not succeeded in increasing investor confidence and growing crypto adoption in the market. there must be another way to grow positive sentiment towards the market.