Is it correct to say the purpose of YC is to seed fund as a lead up to an IPO? Or is the purpose of YC to seed fund to create a blossoming privately-owned prod

Is it correct to say the purpose of YC is to seed fund as a lead up to an IPO? Or is the purpose of YC to seed fund to create a blossoming privately-owned product? I look at a software company like McNeel or Dassault that outlasts dozens of IPOS... from what I see of YC, I don't get the vibe these are even comparable.