It's debatable, but I would say that by going to an ivy league school, you create better connections that come in handy while building a business. The education you receive there is likely better than other schools as well (in terms of being crafted more to churn out business leaders). Do note that other schools also have smaller budgets, which limits the kind of education and resources they can provide students.
Regarding if it plays a factor when raising money or applying for jobs, it definitely does give those founders an extra edge.
What you can you do if you didn't go to an ivy league school? Prove your business model by getting more customers before you start making rounds at Sandy Hill.
It's not that they went to ivy league schools because they were successful, they were successful because of their experience at schools like Stanford and Harvard.
Looking at the startups that get the most VC money, it seems almost like an insiders club for the top schools. i.e. If you didn't go to one, your odds of getting that level of funding are far lower.
I wish someone researched this and posted statistics. It would be an interesting case study.
Your odds would be better. Reason being you'll have more opportunities to interact with VCs through your school affiliations or from attending conferences and events exclusive to those schools.
There are many people, however, who didn't go to an ivy league school like Harvard and still built up rapport with VCs and relationships with successful entrepreneurs to get "in the circle".