In my opinion, IEO is not for crypto startups that are seeking funds to kick start their project but for projects that have raised capital already or have rich advisor and team to fund the project. Fund-raising through IEO can be very challenging for startups that need money to kickstart their project, because they will need large amount of money to conduct their tokensale on good exchanges, as this exchanges only list projects that meet their legal requirements and can also afford to pay their listing fees. So the best means to raise money or capital for new projects is to present their proposal to Venture capital firms or Angel investors.
To some extent, You are right but not all projects collect as much money to simply cover the cost of the IEO.In this case, the need for the IEO is simply a steep advertising but not a way to raise funds for development.About venture firms and angel investors here I fully agree with You.They give the first impetus to the development of startups.